A Belgian police officer was killed in a knife attack in Brussels on Thursday, authorities said, as anti-terrorism prosecutors took over the investigation.

Prosecutor’s spokesman Eric Van Duyse told AFP that federal investigators accepted the charges “because there is a suspicion of a terrorist motive, which has been confirmed or disproved.”

Local media reported that around 1815 GMT an attacker stabbed two officers near Brussels North Train Station before being shot in the legs and abdomen by another police patrol who arrived at the scene.

One of the police officers reportedly died from his injuries after being stabbed in the neck, and both the other police officer who was wounded and the perpetrator were taken to hospital.

A local resident told AFP he heard “five or six gunshots” shortly after the attack.

“Our police officers risk their lives every day to keep our citizens safe. Today’s drama shows this once again,” wrote Belgian Prime Minister Alexander De Croo.

“My thoughts are with the family and friends of the late officer. My sincere hope is that his colleague at the hospital is doing well,” he posted on social media.

Several news outlets reported, without citing their source, that the attacker went to a police station in the city earlier Thursday to warn that he was trying to attack police, but he was not arrested.

Home Secretary Annelies Verlinden said she was “monitoring the situation closely” and was in contact with police and local authorities.

“This violence against our people is unacceptable,” she said.

Justice Secretary Vincent Van Quickenborne said: “Police and prosecutors are doing what they must to investigate these horrific acts.”

Brussels is currently on the trial of those accused of involvement in the 2016 attacks by the Islamic State group that killed 32 people at the city’s main airport and in a crowded metro station.

The trial is the largest ever before a Belgian jury, with 960 civil plaintiffs represented and the sprawling former headquarters of the NATO military alliance converted into a high-security court complex on the outskirts of the city.

Between 2016 and 2018, Belgium witnessed several deadly Islamist terrorist attacks against the police or the military.

The last attack classified as “terrorist” occurred in the city of Liège in May 2018, when a radicalized attacker shot dead two policewomen and a student before being gunned down by officers.