BRUSSELS: Belgian investigators on Wednesday said an Islamic State-style attack that killed three people in the eastern city of Liege was being treated as an act of terrorism.
The bloodshed shocked the eastern industrial city of Liege on Tuesday when the attacker armed with a knife repeatedly stabbed two policewomen before using their own firearms to kill them, a method investigators said was encouraged in online videos by the Islamic State extremist group.
Police were scrambling to unpick the motives of the attacker identified as Benjamin Herman, a 31-year-old drifter with a decade spent in and out of prison for acts of violence and petty crimes, who was out of jail on leave when he attacked.
"The facts are qualified as terrorist murder and attempted terrorist murder," prosecutors' spokesman Eric Van Der Sypt told a news briefing in Brussels.
Van Der Sypt said the assessment was based on several "first elements" from the probe, including "the fact the perpetrator shouted several times shouted 'Allahu akbar' ... and information from state security according to which the perpetrator was in touch with radicalised persons."
But he cautioned that the information dated "from late 2016, early 2017" and had not been confirmed since.
Prosecutors also underlined that the attacker's method -- attacking armed police officers and using their weapon against them -- was a known "modus operandi" of the IS terror group, which claimed deadly attacks in Brussels in 2016.
Amateur footage obtained by AFP showed the gunman shouting "Allahu akbar" (Arabic for "God is greatest") as he walked through the Liege streets during the rampage.
In another video, the suspect darts out of a school where he had holed up into a short and intense burst of police gunfire, after which the man collapses to the ground.
But Interior Minister Jan Jambon urged caution over the extremist angle.
"There are signals that there was radicalisation in the prison but did this radicalisation lead to these actions? There too we can ask ourselves a lot of questions," he told RTL radio.
- Brutal hammer murder -
Special attention is being given to the gruesome killing of an alleged heroin dealer linked to Herman who was bludgeoned to death with a hammer late Monday in a village near the Luxembourg border.
Investigators on Tuesday found the hammer in Herman's car and Jambon said police believed the Liege attacker carried out the killing just hours after getting temporary release from prison.
Prosecutors confirmed Herman was being investigated over the case, saying it was a separate investigation.
As well as the two policewomen, the attacker also shot dead a 22-year-old student sitting in a parked car in central Liege. He then took a female cleaner hostage in the nearby Leonie de Waha school, a public institution with several hundred students aged from two to 18.
The two murdered police officers were identified as Lucile Garcia, 53, who had recently become a grandmother, and Soraya Belkacemi, 45, a mother to 13-year-old twins.
Debate in Belgium was swirling on the country's prison policy with reports that Herman had repeatedly blown the conditions of his temporary leave from jail ahead of his full release set for 2020.
"I feel responsible because I have responsibility for prisons," Belgian Justice Minister Koen Geens told RTBF radio.
Liege, a major city in Belgium's blighted industrial rustbelt, was the scene of another bloody shootout in 2011 when a recent convict killed six people and wounded more than 120 before turning the gun on himself.
Liege police on Tuesday said it was "clear that the assassin's objective was to attack the police" and that one of the four officers wounded had suffered a serious leg injury.
Prime Minister Charles Michel denounced what he called the "cowardly and blind violence" of Tuesday's attack.
- Terror alert -
Belgium has been on alert since authorities in January 2015 smashed a terror cell in the town of Verviers near Liege that was planning an attack on police.
The cell also had links to Abdelhamid Abaaoud, the mastermind of the November 2015 Islamic State attacks on Paris that killed 130 people.
IS suicide attacks then targeted Brussels airport and a metro station, leaving 32 people dead in March 2016.
In August that same year, a machete-wielding man shouting "Allahu Akbar" attacked two policewomen in the industrial town of Charleroi before being shot dead.