UTRECHT, Netherlands (Reuters) - Dutch police arrested a Turkish man suspected of shooting dead three people and wounding five on a tram in the Dutch city of Utrecht on Monday.

Utrecht police announced the suspect, 37-year-old Gokmen Tanis, had been taken into custody.

The city was put into lockdown after the shooting, shortly after the morning rush hour, which authorities initially said was an apparent terrorist attack. Police conducted raids in several locations.

But hours after the shooting, the gunman's motive remained unclear. A prosecutor said it could be for "family reasons" and Turkey's state-run Anadolu news agency, quoting relatives of the gunman, said he had fired at a relative on the tram and had then shot at others who tried to help her.

Helicopters hovered over the usually quiet mediaeval town.

Authorities had raised the terrorism threat in Utrecht province to its highest level, schools were told to shut their doors and paramilitary police increased security at airports, other vital infrastructure and at mosques.

RELATED: Terror level raised following Dutch tram shooting

19 PHOTOS Terror level raised following Dutch tram shooting See Gallery Terror level raised following Dutch tram shooting A body is covered with a blanket next to a tram following a shooting in Utrecht, Netherlands, Monday, March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo/Peter Dejong) Rescue workers install a screen on the spot where a body was covered with a white blanket following a shooting in Utrecht, Netherlands, Monday, March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo/Peter Dejong) A body is covered with a white sheet after a shooting in a tram in Utrecht, Netherlands, Monday, March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo/Peter Dejong) Ambulances are seen next to a tram after a shooting in Utrecht, Netherlands, Monday, March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo/Peter Dejong) Netherlands shaded relief map, highlighted, with THE HAGUE (capital) and UTRECHT locators, lettering SHOOTING, finished graphic Rescue workers install a screen on the spot where a human shape was seen under a white blanket following a shooting in Utrecht, Netherlands, Monday, March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo/Peter Dejong) In this image taken from the Twitter page of Lilian Bruigom, emergency services attend the scene of a shooting in Utrecht, Netherlands, Monday March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (Lilian Bruigom via AP) In this image taken from video, a body lays next to a tram as emergency services attend the scene of a shooting in Utrecht, Netherlands, Monday March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (AP Photo) Emergency services attend the scene of a shooting in Utrecht, Netherlands, Monday March 18, 2019. Police in the central Dutch city of Utrecht say on Twitter that "multiple" people have been injured as a result of a shooting in a tram in a residential neighborhood. (Martijn van der Zande via AP) UTRECHT, NETHERLANDS - MARCH 18: Police take security measures around the scene after a gunman opened fire on tram passengers in Utrecht, Netherlands on March 18, 2019. The attack was carried out at October 24 Square at the central city of Utrecht. The Dutch police is investigating the case as a terrorist attack. (Photo by Abdullah Asiran/Anadolu Agency/Getty Images) UTRECHT, NETHERLANDS - MARCH 18: A view of the scene after a gunman opened fire on tram passengers in Utrecht, Netherlands on March 18, 2019. The attack was carried out at October 24 Square at the central city of Utrecht. The Dutch police is investigating the case as a terrorist attack. (Photo by Abdullah Asiran/Anadolu Agency/Getty Images) Police forces and emergency services stand at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - A gunman opened fire on a tram in the Dutch city of Utrecht on March 18, 2019, killing at least one person and wounding several in what officials said was a possible terrorist incident. (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) Police forces stand near a tram at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - A gunman who opened fire on a tram in the Dutch city of Utrecht on March 18, injuring several people, is on the run, police said. Police only spoke of one gunman but did not rule out the possibility there might be others, the ANP news agency quoted police as saying. (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) UTRECHT, NETHERLANDS - MARCH 18: A view of the scene after a gunman opened fire on tram passengers in Utrecht, Netherlands on March 18, 2019. The attack was carried out at October 24 Square at the central city of Utrecht. The Dutch police is investigating the case as a terrorist attack. (Photo by Abdullah Asiran/Anadolu Agency/Getty Images) EDITORS NOTE: Graphic content / A body lying on the ground is covered near a tram at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - A gunman who opened fire on a tram in the Dutch city of Utrecht on March 18, injuring several people, is on the run, police said. Police only spoke of one gunman but did not rule out the possibility there might be others, the ANP news agency quoted police as saying. (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) Police forces and emergency services stand at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - Several people were wounded in a shooting on a tram in the Dutch city of Utrecht on March 18, police said, with local media reporting counter-terrorism police at the scene. 'A shooting occurred on the 24 Oktoberplein in Utrecht... Multiple people have been injured. The surrounding area has been cordoned off and we are investigating the matter,' Utrecht police said on Twitter. (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) Police forces walk near a tram at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - A gunman who opened fire on a tram in the Dutch city of Utrecht on March 18, injuring several people, is on the run, police said. Police only spoke of one gunman but did not rule out the possibility there might be others, the ANP news agency quoted police as saying. (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) TOPSHOT - Police forces stand at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place. - Several people were wounded in a shooting on a tram in the Dutch city of Utrecht on March 18, police said, with local media reporting counter-terrorism police at the scene. 'Shooting incident... Several injured people reported. Assistance started,' the Utrecht police Twitter account said. 'It is a shooting incident in a tram. Several trauma helicopters have been deployed to provide help.' (Photo by Robin van Lonkhuijsen / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN VAN LONKHUIJSEN/AFP/Getty Images) A traveler waits at the Amsterdam Central station on March 18, 2019 on the national action day for a better pension during which no trains, trams, buses and subways run from 6 a.m. to 7:06 a.m. - Trade unions demand that the state pension age is frozen at 66 years. (Photo by Robin UTRECHT / ANP / AFP) / Netherlands OUT (Photo credit should read ROBIN UTRECHT/AFP/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Dutch Prime Minister Mark Rutte convened crisis talks immediately after the incident, which came three days after a lone gunman killed 50 people in mass shootings at two mosques in the city of Christchurch, New Zealand.

"Our country has today been shocked by an attack in Utrecht... A terrorist motive cannot be excluded," Rutte said.

"The first reports have led to disbelief and disgust. Innocent people have been struck by violence... We are now doing everything we can to find the perpetrator or perpetrators as soon as possible. That is now our complete focus."

The mayor of Utrecht, Jan van Zanen, said three people had been killed and nine injured, three of them seriously. The number of injured was later lowered to five.

Dutch police issued an image of Tanis and warned the public not to approach him.

"FRIGHTENING"

The suspect had previous run-ins with police, the prosecutor said. Local broadcaster RTV Utrecht said earlier the suspect was known to police for both minor and major crimes, including a shooting in 2013.

The shooting took place in Kanaleneiland, a quiet residential district on the outskirts of Utrecht with a large immigrant population.

"It’s frightening that something like this can happen so close to home," said Omar Rahhou, who said his parents lived on a street cordoned off by police. "These things normally happen far away but this brings it very close, awful."

Witness Daan Molenaar, who said he had been sitting at the front of the tram when the shooting started, told national broadcaster NOS he did not believe it was a terrorist attack.

"The first thing I thought was, this is some kind of revenge or something, or somebody who's really mad and grabbed a pistol," he said.

The streets of Utrecht were emptier than usual and mosques in the city kept their doors closed on Monday. Police screened off the site where at least one body lay covered near the tram.

Dutch television showed counter-terrorism units surrounding a house in Utrecht and sniffer dogs being put to work.

Utrecht, the Netherlands' fourth largest city with a population of around 340,000, is known for its picturesque canals and large student population. Gun killings are rare in Utrecht, as elsewhere in the Netherlands.

(Additional reporting by Toby Sterling and Anthony Deutsch; Writing by Gareth Jones; Editing by Janet Lawrence)

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