The Islamic State group has claimed responsibility for Saturday's machete attack on two policewomen in Belgium.
The attack was carried out by one of the Islamic State group's "soldiers", said a statement by the IS-affiliated Aamaq News Agency posted on an IS-linked Twitter account.
The statement said the attack in the city of Charleroi was in response to the "Crusader coalition's" campaign against IS and its self-declared caliphate in Iraq and Syria.
Belgian prosecutors identified the machete-wielding assailant as a 33-year-old Algerian known to police for criminal offences, but not for extremist acts.
The attack on Saturday afternoon is being treated as a terrorist incident, notably because the man shouted "Allahu akbar" - Arabic for "God is great" - as he slashed at the officers outside Charleroi's main police station, Prime Minister Charles Michel said.
The assailant, shot by a third officer, died later in a hospital.
Belgium, a longtime US ally, is a member of the American-led coalition combating IS, and has supplied warplanes to participate in anti-IS operations.
The Belgian Federal Prosecutor's Office said the attacker, who it identified only as KB, had lived in Belgium since 2012.
"Since there are indications that the attack may have been inspired by a terrorist motive, the federal prosecutor's office decided to take over the investigation from the district prosecutor's office of Charleroi," the federal office said in a statement.
The office said two police searches were carried out overnight in the southern Belgian city, but that no further information about the investigation would be made public.
Broadcast media including state-owned RTBF said KB was in Belgium illegally despite receiving two separate orders from government authorities to leave. PM Michel did not directly confirm the reports, but he told RTL television that more must be done to combat illegal immigration - saying it was difficult to persuade Algeria to accept the return of its nationals.
Both policewomen were "severely injured in the face and neck" in the attack, the federal prosecutors' statement said. RTL said both were placed in an artificial coma to allow surgeons to operate on them.
Michel said the prosecutors were treating the attack on the officers as a case of "attempted terrorist murder." The PM cut short his holiday in the south of France following the Charleroi attack, which had some police unions calling for greater protection for police officers and installations.
"We must keep a cool head," he said. "We must avoid panic, of course - not give in to terror. That's the trap that has been set for us."
Belgium has been on high alert since the March 22 suicide bombings claimed by Islamic State extremists that killed 32 people in Brussels.
Many of the perpetrators of the November 13 carnage in Paris that killed 130 people were also residents of Belgium. That attack was also claimed by IS.