STOCKHOLM -- A hijacked beer truck plowed into pedestrians at a central Stockholm department store on Friday, killing four people, wounding 15 others and sending screaming shoppers fleeing in panic in what Sweden's prime minister called a terrorist attack.

A nationwide manhunt was launched and one person was arrested following the latest use of a vehicle as a weapon in Europe.

Nearby buildings were locked down for hours in the heart of the capital -- including the country's parliament -- and the main train station and several large malls were evacuated.

"Sweden has been attacked," Prime Minister Stefan Lofven said in a nationally televised press conference. "This indicates that it is an act of terror."

Later Friday night, Lofven laid a bouquet of red roses and lit a candle near the site of the attack.

"The country is in a state of shock," he said. "The aim of terrorism is to undermine democracy. But such a goal will never be achieved in Sweden."

There was no immediate claim of responsibility for the attack. Police arrested a man in Marsta, a northern Stockholm suburb close to the city's international airport, as a possible suspect.

The stolen beer truck travelled for more than 500 yards (meters) along a main pedestrian street known as the Drottninggatan before it smashed into a crowd outside the upscale Ahlens department store about 3 p.m. It came to rest in the entrance to the building. TV footage showed smoke coming out of the store after the crash.

"People were screaming and running in all directions," said Brandon Sekitto, who was in his car nearby. "(The truck) drove straight into the Ahlens entrance."

"I saw the driver, a man in black who was light around the face," Brandon told Swedish daily Dagens Nyheter. "Some women were screaming, 'Run! Run!"'

Late into the night, forensic experts in full white suits could be seen working on the truck, collecting evidence.

Although there was initial confusion on the number of victims, police told reporters in the evening that four people had been killed and 15 were wounded, nine of them seriously.

Authorities evacuated the city's nearby Central Station, a hub for regional trains and the subway system. All trains to and from the main station were halted and several large shopping malls in Stockholm were shut down. Sweden's national theatre, Dramaten, cancelled three performances Friday evening.

Jan Evensson of the Stockholm police told a news conference that the man who was arrested looked like the person depicted wearing a greenish hood in a surveillance camera photo that police released earlier. He said police were "particularly interested" in him.

"We continue to investigate at full force," Evensson said, urging people not to go to central Stockholm on Friday night.

Stefan Hector of Sweden's national police said the working hypothesis was that "this is an act of terror."

"We will be working as long as necessary" to determine who was responsible, Stockholm police spokesman Lars Bystrom told The Associated Press.

The Swedish brewery Spendrups said one of its trucks had been hijacked just a few blocks from the crash scene earlier Friday.

"It is one of our delivery trucks. In connection with a delivery to a restaurant called Caliente, someone jumped into the truck and drove it away while the driver was unloading his delivery," Spendrups spokesman Marten Luth told the Swedish news agency TT.

The beer company's truck driver was not injured, he said.

The truck crash appeared to be the latest attack in Europe using a vehicle.

In an attack last month claimed by the Islamic State group, a man drove into a crowd on London's Westminster Bridge, killing three people and injuring many others before stabbing a policeman to death. He was shot and killed by police. A fourth person, a woman thrown into the Thames by the force of the car attack, died Thursday.

The IS group also claimed responsibility for a truck attack that killed 86 people in Nice, France, in July 2016 during a Bastille Day festival, as well as another truck attack that killed 12 people at a Christmas market in Berlin.

Swedish King Carl XVI Gustaf cut short a visit to Brazil on Friday to return home and sent the royal family's condolences to the families of the truck attack victims.

Lofven said his Social Democratic Party was still planning to hold its annual convention this weekend in Goteborg, Sweden's second-largest city.

Condolences poured into Sweden. In neighbouring Finland, President Sauli Niinisto said he was shocked by the "maniac act of terror," adding "every terror attack is to be equally condemned. But it touches us deeply when such an attack takes place in our Nordic neighbourhood."

Danish Prime Minister Lars Loekke Rasmussen called the attack a cowardly attempt "to subdue us and the peaceful way we live in Scandinavia."

Paris Mayor Anne Hidalgo said the Eiffel Tower's lights will be turned off from midnight Friday in homage. She expressed her "strong emotion" over "this new terrorist attack of immense cowardice."

EU Council President Donald Tusk said in a tweet that "my heart is in Stockholm this afternoon. My thoughts are with the victims and their families and friends of today's terrible attack."

European Commission President Jean-Claude Juncker said "one of Europe's most vibrant and colorful cities appears to have been struck by those wishing it -- and our very way of life -- harm."

Juncker also said "an attack on any of our (EU) member states is an attack on us all" and that Sweden can count on EU help.

In February, U.S. President Donald Trump suggested that Sweden could be the next European country to suffer the kind of extremist attacks that have devastated France, Belgium and Germany. Two days after his remarks, a riot broke out in predominantly immigrant suburb of Stockholm where police opened fire on rioters, a surprise to many Swedes who aren't used to officers using guns.

Friday's truck crash was near the site of a December 2010 attack in Stockholm in which Taimour Abdulwahab, a Swedish citizen who lived in Britain, detonated a suicide bomb, killing himself and injuring two others.

Abdulwahab had rigged a car with explosives in the hope the blast would drive people to Drottninggatan -- the street hit Friday -- where he would set off devices strapped to his chest and back. The car bomb never went off, and Abdulwahab died when one of his devices exploded among panicked Christmas shoppers.

Olsen reported from Copenhagen, Denmark. Matti Huuhtanen and Jari Tanner in Helsinki, Finland, contributed

A timeline of the incident (all times local):

9:55 p.m.

Swedish Prime Minister Stefan Lofven says "the country is in a state of shock" over the stolen beer truck attack that killed four people and wounded 15 others in downtown Stockholm.

Lofven said "the aim of terrorism is to undermine democracy. But such a goal will never be achieved in Sweden."

Police have arrested one suspect in the truck attack but would not say if they are hunting for any others. They discouraged people from going into central Stockholm on Friday night, and the national theatre, which is near the crash site, cancelled three plays.

Lofven said in a national televised address that his Social Democratic Party was still planning to hold its annual convention this weekend in Goteborg, Sweden's second-largest city.

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9:40 p.m.

Swedish police say they have arrested one man "whom we are particularly interested in" in the deadly stolen beer truck attack in Stockholm.

Jan Evensson from the Stockholm police told a news conference late Friday the man was arrested in Marsta, a northern Stockholm suburb close to the city's international airport, Arlanda. He says the man was "in the vicinity" of the truck crash that killed four people and wounded 15 others on a pedestrian street in the Swedish capital.

He says the suspect was spotted by a police patrol and was in a police photo released earlier Friday wearing a greenish hood at the top of an escalator.

Stefan Hector of the Sweden's national police says "we have a working hypothesis this is an act of terror."

Evensson urged people not to go into central Stockholm for the time being.

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9 p.m.

Stockholm police have raised the toll in the beer truck attack to 4 dead, 15 wounded.

The news comes as Swedish police launched a nationwide manhunt for the person or persons who drove a stolen beer truck down a pedestrian street in the Swedish capital and crashed it into a department store Friday afternoon.

Stockholm police say one person "that can have some kind of connection" to the attack has been arrested.

It's not clear if that person is the man in a police photo released earlier Friday, wearing a greenish hood at the top of an escalator.

Police are holding a news conference in 30 minutes on the case.

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8:45 p.m.

The Stockholm County Council says three people have been killed and 15 wounded in the beer truck attack, nine of them seriously.

Swedish police have launched a nationwide manhunt for the person or persons who drove a stolen beer truck down a pedestrian street in Stockholm and crashed it into a department store Friday afternoon.

Stockholm police says one person "that can have some kind of connection" to the attack has been arrested.

The Swedish daily Aftonbladet reported that a man with minor injuries had been arrested and has confessed to being behind the beer truck crash.

Swedish Prime Minister Stefan Lofven has described the crash as a terror attack.

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8:40 p.m.

Sweden's national theatre, Dramaten, located a stone's throw from where a hijacked beer truck crashed into an upscale department store, has cancelled three plays Friday evening.

The theatre says on its web page that people who had bought tickets could either have refunds or change their dates to other shows or days.

Swedish Prime Minister Stefan Lofven has described the crash as a terror attack and says it killed at least two people.

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8:20 p.m.

Danish Prime Minister Lars Loekke Rasmussen says the truck crash that killed at least two people in neighbouring Stockholm "is a cowardly attempt to subdue us and the peaceful way we live in Scandinavia."

Loekke Rasmussen says "it hurts deep inside my heart that our Swedish brothers have been exposed to a so abominable attack."

Latvia's Foreign Ministry "condemns in the strongest terms the terror attack."

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8 p.m.

Swedish police have launched a nationwide manhunt for the person or persons who drove a stolen beer truck down a pedestrian street in Stockholm and crashed it into a department store.

Police released photos of a man wearing a greenish hood at the top of an escalator, believed to be somehow "connected to the event."

Swedish Prime Minister Stefan Lofven described the crash as a terror attack and said two people were killed.

Sweden's police chief Dan Eliasson said they have had no contact with "the person or persons" who drove the stolen truck but police started "a preliminary investigation of suspected terrorist crimes."

The head of Sweden's security agency, Anders Thornberg, said they are "conducting intensive intelligence work to identify the person or persons behind the attack."

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7:30 p.m.

Swedish police say they are beginning a "preliminary investigation into suspected terrorist crimes" after a deadly truck crash in Stockholm.

The head of Sweden's security agency, Anders Thornberg, said agents are "conducting intensive intelligence work to identify the person or persons behind the attack."

Swedish Prime Minister Stefan Lofven described Friday's deadly truck attack in central Stockholm as a "terrorist attack." Police, however, say they have no details about the attacker or attackers and no one in custody.

No one has claimed responsibility for crashing a stolen beer truck into a major department store in the city. Lofven says two people have died in the attack. Swedish media are reporting more deaths but police won't confirm those reports.

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6:50 p.m.

The mayor of London, where five people were killed in a vehicle and knife attack last month, says the British capital "stands united with Stockholm" after Friday's deadly truck crash.

Sadiq Khan says it appears Sweden has "seen a despicable act of terrorism aimed at harming innocent people and attacking our shared values of democracy, freedom, justice and tolerance."

He says Londoners know what it is to suffer from terrorism, and "we share a steely determination with the people of Stockholm that we will never allow terrorists to succeed."

Swedish police say several people were killed and injured after a stolen beer truck careened down a pedestrian street and into a department store.

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6:10 p.m.

The foreign ministers of Germany and France are reacting with shock to the deadly truck attack in Stockholm.

Sigmar Gabriel and Jean-Marc Ayrault noted Sweden's efforts for human rights, peace and justice around the world.

In a joint statement Friday, they said that "this makes the shock about the pictures coming from the heart of Stockholm that much greater."

Both Germany and France experienced deadly truck attacks last year that were claimed by the Islamic State group.

Separately, German President Frank-Walter Steinmeier expressed solidarity with the victims in Stockholm "and all people in Sweden."

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6:05 p.m.

Paris' mayor says the Eiffel Tower will go black from midnight in homage to Stockholm after a truck ran into a crowd of people with deadly consequences.

Anne Hidalgo, in a communique Friday, expressed her "strong emotion" over "this new terrorist attack of immense cowardice."

Hidalgo also expressed solidarity with the victims and their loved ones, as well as with Stockholm Mayor Karin Wanngard, "in this particularly difficult ordeal."

Hidalgo is no stranger to bloodshed in her city, following attacks in 2015 on satirical newspaper Charlie Hebdo in January and on various sites in November of the same year including at the Bataclan concert hall.

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6 p.m.

Russian President Vladimir Putin has sent a telegram of condolence to Sweden's monarch in the wake of the fatal truck crash in Stockholm that officials say was likely a terror attack.

"In our country, people know, and not by hearsay, about the atrocities of international terrorism. At this difficult time, Russians mourn together with the people of Sweden," Putin said in the message to King Carl XVI Gustaf that was published on the Kremlin website Friday.

A suicide bomb on a St. Petersburg subway train on Monday killed 13 passengers.

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5:45 p.m.

Swedish police say they cannot say how many people were killed or injured when a truck ran into a crowd in downtown Stockholm, and they have not found the driver.

"We have no contact with the person or persons who drove the truck," Sweden's top police chief, Dan Eliasson, told a news conference.

"Right now we have no one arrested," said Jan Evensson of the Stockholm police who urged people not to drive into central Stockholm.

Sweden's security agency boss Anders Thornberg said the SAPO agency was working with the ordinary police in the case, adding "we worked on a simlar sceanario last week."

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5:30 p.m.

Norwegian police, who are normally unarmed, have decided to allow officers in some major cities to carry weapons following an apparent attack in the centre of the Swedish capital, Stockholm, national news agency NTB said.

Oslo Police spokeswoman Marita Aune confirmed to The Associated Press that officers in Oslo will begin to carry weapons with immediate effect.

Several people are believed to have been killed and several others injured after the lorry ran into a crowd of people on a pedestrian street in central Stockholm.

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5:30 p.m.

Swedish police say there are several dead and several injured after a truck ran into a crowd of people in downtown Stockholm.

In a statement Friday, they said that they cannot exclude this is an act of terror based on other events in Europe.

Swedish Prime Minister Stefan Lofven, who was returning to Stockholm from central Sweden, said that everything indicates it was "a terror attack."

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5 p.m.

Sweden's King Carl XVI Gustaf said in a brief statement that the Swedish royal family had noted the apparent attack in central Stockholm "with dismay" and sent condolences to the families of the victims and injured.

"We follow developments but as of now our thoughts go to the victims and their families," he said.

In neighbouring Finland, President Sauli Niinisto said he is shocked by the "maniac act of terror" in Stockholm.

"Every terror attack is to be equally condemned. But it touches us deeply when such an attack takes place in our Nordic neighbourhood," Niinisto said in a statement.

Finnish Foreign Minister Timo Soini described on Twitter the events in Stockholm as "a shocking incident" and the Helsinki police said separately that it will tighten security measures in the centre of the Finnish capital.

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4:55 p.m.

Top European Union officials have expressed their condolences to the families of victims of the truck crash at a Stockholm department store and praised the courage of first responders.

EU Council President Donald Tusk said in a tweet Friday that "my heart is in Stockholm this afternoon. My thoughts are with the victims and their families and friends of today's terrible attack."

European Commission President Jean-Claude Juncker said that "one of Europe's most vibrant and colorful cities appears to have been struck by those wishing it - and our very way of life - harm."

Juncker said "an attack on any of our (EU) member states is an attack on us all" and that Sweden can count on EU help.

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4:50 p.m.

Chancellor Angela Merkel's spokesman says the German government's "thoughts are with the people in Stockholm, the injured, the relatives, first responders and police" after a truck crashed into a department store, killing several people.

Steffen Seibert said Friday on Twitter following the apparent attack in Sweden: "We stand together against terror."

Germany experienced a truck attack on a busy Berlin Christmas market in December, in which 12 people were killed.

The attacker, a 24-year-old Tunisian, was shot dead in Italy days later.

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5:30 p.m.

Norwegian police, who are normally unarmed, have decided to allow officers in some major cities to carry weapons following an apparent attack in the centre of the Swedish capital, Stockholm, national news agency NTB said.

Oslo Police spokeswoman Marita Aune confirmed to The Associated Press that officers in Oslo will begin to carry weapons with immediate effect.

Several people are believed to have been killed and several others injured after the lorry ran into a crowd of people on a pedestrian street in central Stockholm.

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5:30 p.m.

Swedish police say there are several dead and several injured after a truck ran into a crowd of people in downtown Stockholm.

In a statement Friday, they said that they cannot exclude this is an act of terror based on other events in Europe.

Swedish Prime Minister Stefan Lofven, who was returning to Stockholm from central Sweden, said that everything indicates it was "a terror attack."

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5 p.m.

Sweden's King Carl XVI Gustaf said in a brief statement that the Swedish royal family had noted the apparent attack in central Stockholm "with dismay" and sent condolences to the families of the victims and injured.

"We follow developments but as of now our thoughts go to the victims and their families," he said.

In neighbouring Finland, President Sauli Niinisto said he is shocked by the "maniac act of terror" in Stockholm.

"Every terror attack is to be equally condemned. But it touches us deeply when such an attack takes place in our Nordic neighbourhood," Niinisto said in a statement.

Finnish Foreign Minister Timo Soini described on Twitter the events in Stockholm as "a shocking incident" and the Helsinki police said separately that it will tighten security measures in the centre of the Finnish capital.

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4:55 p.m.

Top European Union officials have expressed their condolences to the families of victims of the truck crash at a Stockholm department store and praised the courage of first responders.

EU Council President Donald Tusk said in a tweet Friday that "my heart is in Stockholm this afternoon. My thoughts are with the victims and their families and friends of today's terrible attack."

European Commission President Jean-Claude Juncker said that "one of Europe's most vibrant and colorful cities appears to have been struck by those wishing it - and our very way of life - harm."

Juncker said "an attack on any of our (EU) member states is an attack on us all" and that Sweden can count on EU help.

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4:20 p.m.

Photos at the scene in downtown Stockholm show that the truck which crashed into a major department store, killing several people, is a large beer truck.

The Aftonbladet daily says Swedish beermaker Spendrups said its truck had been carjacked earlier Friday. Photos showed the beer truck sticking out of the Ahlens department store.

Swedish broadcaster SVT said shots were fired at the scene, though it wasn't clear who fired them.

Swedish Prime Minister Stefan Lofven says the truck crash "is an act of terror" that has killed at least two people. He says one person has been arrested in the attack.

Swedish media report that up to five people have been killed, and Sweden's intelligence agency says many people have been injured in the crash.

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4:10 p.m.

Swedish Prime Minister Stefan Lofven says everything indicates that a truck which has crashed into a major department store in downtown Stockholm is "a terror attack."

Lofven says at least two people have been killed in the attack Friday afternoon on the Ahlens store.

Broadcaster SVT says at least five people have been killed in the attack but police could not immediately confirm that. Swedish radio says at least three people have died.

The Aftonbladet daily says Swedish beermaker Spendrups said its truck had been carjacked earlier Friday.

The most recent attack in Stockholm was on Dec. 11, 2010, when an Iraqi-born Swede, Taimour Abdulwahab al-Abdaly, detonated two devices, including one that killed him, in central Stockholm.

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4:00 p.m.

Swedish radio says a truck has crashed into an upscale department store in central Stockholm, killing at least three people.

Swedish police are urging people to avoid central Stockholm around the downtown Sergels Torg square, and Swedish news agency TT says subway traffic has been shut down in the area.

Broadcaster SVT says at least five have been killed but police could not immediately confirm.

Sweden's Intelligence Agency says on its web page that there is "a large number of injured" in the truck crash.

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3:40 p.m.

Pictures published by Swedish tabloid Aftonbladet show that a truck has ploughed into the upscale Ahlens department store in the Swedish capital of Stockholm. Swedish radio says Friday that three people have been killed in the crash and Swedish broadcaster SVT says shots have been fired.

People in the area are fleeing the scene.

Witness Jan Granroth told Aftonbladet, another daily that "we stood inside a shoe store and heard something ... and then people started to scream." He says "I looked out of the store and saw a big truck."

The store is part of a Sweden-wide chain. The building includes several stores at the street level.

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3:10 p.m.

Swedish media say a truck has crashed into a department store in central Stockholm, killing three people.

Swedish radio says Friday that three people have been killed in the crash and Swedish broadcaster SVT says shots have been fired. People in the area are fleeing the scene.

The Swedish news agency TT says several people have been rushed away in ambulances, and live television footage showed smoke coming out of the department store that the truck smashed into.

Swedish police said say they have received calls about a person who has injured others driving a vehicle on the central Stockholm street of Drottninggatan. Police spokeswoman Towe Hagg says people have been injured but she would not confirm the deaths.

Social media posts from witnesses on the ground in Stockholm

Something's happening on Drottninggatan and around Stockholm. pic.twitter.com/YPbrZSe5Mb — Johnny Chadda (@johnnychadda) April 7, 2017