Dutch authorities have caught the man suspected of opening fire on a tram in the Dutch city of Utrecht, killing three people and injuring five others.

Gokmen Tanis, 37, who has had previous run-ins with law enforcement, was arrested on Monday night, police said.

Dutch authorities are considering "a possible terrorist motive" for the incident, which happened in 24 October Square at 10:45 a.m. (5:45 a.m ET) Monday. Utrecht Mayor Jan van Zanen said the motive behind the attack is "still unclear."

A second suspect has also been taken into custody, van Zanen said, adding that it's not clear what his involvement was in the shooting.

CCTV supplied by Utrecht police in the Netherlands investigating a shooting incident.

At a news conference, Rutger Jeuken from the public prosecution service said authorities are considering that the attack had terrorist motives, and maybe others.

"The first indication of what has happened and the statements that have been made and the traces that have been found, we certainly consider a terrorist motive; however we don't exclude other motives," Jeuken said.

During the manhunt, an image believed to be of Tanis, who was born in Turkey, was taken from security camera footage on board the tram and circulated by Dutch police. It was time-stamped at 10:41, roughly four minutes before the incident took place.

Earlier, the Netherlands' national coordinator for Security and Counterterrorism, Pieter-Jaap Aalbersberg, tweeted, "Crisis team is activated."

Police officers at the scene of a shooting on a tram in Utrecht's 24 October Square.

Authorities downgraded the terror threat level for the province of Utrecht from 5 -- the highest, or most critical -- to level 4 after Tanis' arrest, Aalbersberg said on Twitter on Monday evening.

Following the incident, three rescue helicopters were sent to the scene -- which has since been cordoned off -- to monitor the situation, police spokesman Joost Lanshage said.

Utrecht police also said a Renault Clio was carjacked just before the shooting, and was later found 2.6 miles away.

Photos from the vicinity posted on social media show the tram stopped in its tracks, with police tape surrounding the area and multiple emergency vehicles nearby.

A CNN crew observed a tarpaulin in front of one section of the tram, which is believed to be shielding a body.

Vincent van Roon witnessed the shooting from his office.

"I was there at the moment of the shooting. I'm in a building next to the tram. I heard the shooting and people came into the building, hiding," he said.

Van Roon recalled seeing a heavy police response and medical personnel working on one of the wounded in the street "for a long time."

At a news conference Monday evening, Prime Minister Mark Rutte expressed his condolences to those who had lost a family member in the attack that happened "literally in the heart of our country."

While "questions and rumors abound," Rutte said, "the motives for the attack are still unclear."

"For now, we are overcome by a sense of horror and disbelief at the terrible events of today," he said.

In a statement, the Turkish Ministry of Foreign Affairs expressed condolences for the victims and said Turkey "strongly" condemned the attack, "regardless of the identity of the perpetrator and the motivation behind it."

"In the face of this attack we are in full solidarity with the Dutch people and government," it said.

In response to the shooting, police in Rotterdam -- a city around 60 kilometers (37 miles) away from Utrecht -- have increased security around mosques and transport stations in the city, according to a post on their official Twitter account.

The Netherlands have largely escaped terror incidents in recent years. But Dutch police previously foiled what they described as a major terrorist attack last September when they arrested seven individuals in Rotterdam.

Earlier that month, a man was shot by police at Amsterdam's central railway station after stabbing two American tourists. Authorities said the suspect had a "terrorist motive" but was believed to have acted alone.

CORRECTION: This story has been updated to correct the duration of the critical threat level, and to correct the spelling of the Utrecht Mayor's name, Jan van Zanen.

Source: CNN