Hours after a hijacked beer truck slammed into a department store in central Stockholm on Friday, killing at least four people and wounding many more, Swedish police said they arrested a man in the northern part of the city.

Police spokesman Jan Evensson told a news conference the suspect had been featured in a photo authorities released earlier Friday of a man wearing a greenish hood at the top of an escalator.

Evensson said the man "in the vicinity" of the crash and was "someone whom we are particularly interested in." The suspect was spotted by a police patrol and arrested in Marsta, close to Stockholm's international airport, Arlanda.

Sky News also reported two men have been questioned in relation to the attack. Police spokesman Lars Bystrom said: "I can confirm that we have taken in two people for questioning, but that does not necessary mean that they are suspects."

PHOTOS: TRUCK PLOWS INTO SWEDEN DEPARTMENT STORE

As many as 15 people were hurt, nine of them seriously, according to the Stockholm County Council. Police late Friday raised the death toll from three to four.

Sky News reported that police believed the attacker had run away toward the subway station. All subway traffic was halted.

"Sweden has been attacked. Everything points to the fact that this is a terrorist attack," Lofven told reporters during a visit in western Sweden.

There was no immediate claim of responsibility for Friday's attack, but vehicles have been common weapons in recent extremist attacks.

SWEDEN TRUCK ATTACK FOLLOWS STRING OF SIMILAR VEHICLE ASSAULTS

Police said a truck ran over the crowd at Ahlens department store in the afternoon. People in the downtown area ran in panic, and Stockholm's Central Station for trains and the subway, which is a few hundred yards from the scene, was evacuated.

Spokeswoman Towe Hagg would not confirm reports of shots fired in other parts of the city.

A government source told Reuters all Swedish government offices had been closed. All ministers were safe, the source said.

Sweden's King Carl XVI Gustaf said in a brief statement that the Swedish royal family had noted the attack "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.

SWEDEN TORN OVER HOW TO HANDLE INCOMING TERRORISTS

U.S. Homeland Security officials say they are monitoring the situation.

Chancellor Angela Merkel's spokesman said the German government's "thoughts are with the people in Stockholm, the injured, the relatives, first responders and police."

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

Russian President Vladimir Putin has sent a telegram of condolence to Sweden's monarch saying "Russians mourn together with the people of Sweden."

Photos from the scene showed a beer truck sticking out of the department store, and Aftonbladet daily reported that Swedish beer maker Spendrups said one of its trucks had been carjacked earlier Friday.

"It's one of our distribution vehicles which runs deliveries. During a delivery to the restaurant Caliente someone jumped into the driver's cabin and drove off with the car, while the driver unloads," communication director Mårten Lyth told TT news agency.

POLICE IN NORWAY TO BEGIN CARRYING WEAPONS AFTER STOCKHOLM ATTACK

Live television footage showed smoke coming out of the upscale Ahlens department store on Drottninggatan Street, which the truck smashed into. The department store is part of Sweden-wide chain.

"We stood inside a shoe store and heard something ... and then people started to scream," witness Jan Granroth told the Aftonbladet daily. "I looked out of the store and saw a big truck."

A witness said the truck came out of nowhere, Sky News reported.

“I went to the main street when a big truck came out of nowhere. I could not see if anyone was driving it but it got out of control,” the person said. “I saw at least two being run over. I ran as fast as I could from there".

Europe has reeled from a string of terror attacks involving drivers ramming trucks into populated areas. In July 2016, a truck plowed into a crowd at a waterfront promenade in the French tourist hotspot of Nice, killing 86 people. Police killed the driver, Mohamed Lahouiaej Bouhlel. The Islamic State terror group claimed responsibility.

Just over two weeks ago in London, a driver linked to radical Islam crashed his rented SUV into a crowd on Westminster Bridge before attacking an officer on the grounds of Parliament. A fifth victim of his rampage died Friday: a Romanian woman who fell into the river below. Dozens of other people were wounded. The killer, Khalid Masood, was shot dead at Parliament.

AHLENS DEPARTMENT STORE FAST FACTS

At about this time last year, the Iraqi government warned Sweden that ISIS may have been plotting to attack civilian targets in Stockholm, NBC News reported.

Sweden has produced more ISIS fighters per capita than almost any other European nation, the International Center for the Study of Radicalization and Political Violence reported last year.

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

Abdulwahab rigged a car with explosives in the hope that 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.

Fox News' Catherine Herridge and the Associated Press contributed to this report.