A gunman shot dead three people, two of them policemen, in the eastern Belgian city of Liege on Tuesday before being killed by elite officers, prosecutors told AFP.
Authorities say he attacked two female police officers with a knife, inflicting multiple stab wounds.
Dulieu said the attacker then shot and killed a 22-year-old man in a vehicle who was leaving a parking space outside a nearby high school.
The attacker also shot dead a 22-year-old man in a nearby auto.
Belgian media citing anonymous security officials reported that the suspect is a 36-year-old man with a history of small-time theft and drug violations who had been given a temporary release from prison on Monday for an appointment, after which he did not return.
The city's public prosecutor confirmed the attack was being investigated as a terrorist incident.
Belgium's anti-terror officials were monitoring the situation, Interior Minister Jan Jambon said on Twitter.More news: Update on Facebook App Investigation and Audit
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"He is suspected of having been radicalised (in prison)".
Belgium remains on high alert after attacks in 2016 claimed by the Islamic State group left 32 people dead.
Liege police chief Christian Beaupere said it was "clear that the assassin's objective was to attack the police".
A Belgian lawmaker said he had been on an anti-terrorist police watchlist after being radicalized in jail, apparently as a convert to Islam - raising questions about why he seems to have been freed unsupervized and expected to return.
Video posted on social media appeared to show people running, and approximately six gunshots could be heard.
Charles Michel, Belgium's Prime Minister, condemned the "blind and cowardly violence" in Liege and offered his support for the victims and their families. The King is there with Prime Minister Charles Michel and is now being updated on the situation.
The national crisis centre, on high alert since past attacks by Islamic State in Paris and Brussels, said it was looking into whether terrorism might have been a motive for today's attack in Belgium's third city. Police later killed the attacker, and other officers were wounded in the shooting.
- Police officers arrived at the school and the assailant opened fire, wounding several of them in the legs.