The Netherlands Police on Monday said they arrested a man who had allegedly killed at least three people and injured five others in a tram in Utrecht city on Monday. Dutch anti-terrorism co-ordinator Pieter-Jaap Aalbersberg had earlier said there may be more than one attacker.

The authorities identified the attacker as 37-year-old Turkish man Gokmen Tanis, BBC reported. Aalbersberg said the threat level had been reduced from 5, the highest, to 4.

The shooting began at 10.45 am local time (3.15 pm India time) at 24 Oktoberplain, a square outside the city centre. Three rescue helicopters were sent to the scene, police spokesperson Joost Lanshage had said, according to CNN.

The police said they have set up a telephone line for information on the attack.

“Investigation into shooting incident is underway,” the police wrote on Twitter. “We also take into account a possible terrorist motive.”

Utrecht University was under shutdown mode, BBC reported. The administration had suspended train services to the Utrecht Central station and mosques across the city have reportedly been closed due to security concerns.

Dutch Prime Minister Mark Rutte cancelled his meeting with his coalition members and said he is “deeply concerned” about the situation, BBC reported.