Dutch authorities have caught the man suspected of opening fire on a tram in the Dutch city of Utrech, 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 Zaben said that the motive behind the attack is "still unclear."

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

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."

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

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

Prime Minister Mark Rutte told CNN affiliate RTL that he was "very concerned" about the incident.

In a later news conference, Rutte called the shooting "an attack [on] our society, an attack on our tolerant and open society."

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.