Police in the central Dutch city of Utrecht were hunting for a gunman on Monday after a shooting on a tram that left at least three people dead. Officials said it was possible the attack had a "terrorist motive."

Police, including heavily armed officers, flooded the area after gunfire erupted on the tram at a busy intersection at the October 21st Square station. Utrecht Mayor Jan van Zanen said three people were killed and at least nine others injured in the attack.

The shooter remained at large, prompting the Dutch government to put the country's military police on "extra alert" at airports and "vital buildings" amid a manhunt.

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In a tweet, Utrecht Police said they were looking for 37-year-old Turkish national Gökmen Tanis in connection with the shooting, but they did not explicitly identify him as a suspect. The tweet showed a photo of the man, which appeared to come from a security camera on a tram or bus.

The tweet warned residents not to "approach him yourself," but to immediately call the police if he was spotted.

De politie vraagt u uit te kijken naar de 37-jarige Gökman Tanis (geboren in Turkije) in verband met het incident vanmorgen aan het #24oktoberplein in Utrecht.

Benader hem niet zelf maar bel direct de opsporingstiplijn 0800-6070 pic.twitter.com/QZ88s3Wl0k — Politie Utrecht (@PolitieUtrecht) March 18, 2019

Heavily armed anti-terror officers gathered in front of an apartment building just 200 yards from the scene of the deadly attack not long after the shooting. It was unclear whether the police believed the shooter could be holed up in the building. They were apparently holding their positions and awaiting further orders.

"In Utrecht there was a shooting at several locations," Netherlands Counter-Terrorism Agency head Pieter-Jaap Aalbersberg told a news conference. "A lot is still unclear at this point and local authorities are working hard to establish all the facts. What we already know is that a culprit is at large.

Dutch Prime Minister Mark Rutte called the situation "very worrying" and the country's counterterror coordinator said in a tweet that a crisis team was meeting to discuss the incident.

Police forces walk near a tram at the 24 Oktoberplace in Utrecht, on March 18, 2019 where a shooting took place Getty

Dutch police urged schools to keep their doors shut and locked, and the terror alert level in the Utrecht region was elevated to five, the highest possible.

Holland's gun laws

The shooting in Holland came just three days after a terrorist attack in New Zealand by a white supremacist that left 50 people dead at two mosques. The suspect left a 74-page manifesto online that made it clear one of his objectives was to stoke the debate about firearms legislation in the U.S.

On Monday, New Zealand Prime Minister Jacinda Ardern said her government had agreed to gun law reforms within 72 hours of the attack. The Australian suspect purchased all the weapons used in the attack legally in New Zealand.

In Holland, civilian gun ownership is regulated to the point that most residents consider it flat-out illegal.

There is an elaborate registration and application process to get a firearms license, and most people would need to show membership in a sport shooting association to obtain one. Guns for self defense, kept in the home, are extremely rare in the country.

Anyone who applies for a firearms license must submit their application in person, be present when their home or business is checked for strict safe-storage compliance, provide at least three personal references and undergo a mental health examination.