Pictured: Police officers and bystander killed in Belgium gun attack

The two female police officers and a civilian shot dead in an attack in the Belgian city of Liege have been named.

Soraya Belkacemi, 53, and Lucille Garcia, 45, were killed when a prisoner on day leave from jail stole their handguns on Tuesday.

The gunman also killed Cyril Vangriecken, a 22-year-old male car passenger on the Boulevard d'Avory, before taking a female cleaner hostage at a nearby high school.

The cleaner was released when police shot dead the attacker, who has been named by local media as Belgian national Benjamin Herman.

The 36-year-old petty criminal and drug dealer was released from prison on Monday for a few hours but he failed to return, according to media reports.

Belgian Prime Minister Charles Michel said Herman had been mentioned indirectly in state security reports on radicalisation, but was not on a terror watchlist as services had found "no reason to give him such a qualification".

Media reported that the suspect had been radicalised in prison, and an AFP source close to the investigation said he had been reported as belonging to the "entourage of an Islamist recruiter".

But justice minister Koen Geens said there was no consistent information for the claim, adding that the case was not "clear cut" and that Herman "certainly was not someone who could clearly be qualified as radicalised".

A senior official at the federal prosecutor's office has said "there are indications it could be a terror attack", but Belgium's crisis centre has said there is no reason to raise the anti-terror alert for now.

Officials said Herman approached the officers, aged 45 and 53, from behind and stabbed them repeatedly before taking their handguns and shooting them.

Prosecutor Philippe Dulieu said: "Armed with a knife, the suspect followed and attacked two police officers, and used their own firearms to kill them."

"He continued on foot, attacking a parked vehicle where he opened fire on a 22-year-old man in the passenger seat. The young man died.

"He then continued and entered the Leonie de Waha school. He took a woman working there as hostage.

"Police intervened, he came out firing on the police officers, wounding several before he was killed."

La Libre Belgique newspaper quoted a police source as saying the gunman shouted the Arabic words "Allahu Akbar" - God is great.

The governor of Liege province, Herve Jamar, said no-one was injured during the high school hostage-taking and all students were safe.

A senior official at the prosecutor's office told reporters "there are indications it could be a terror attack".

Interior minister Jan Jambon said the anti-terrorist crisis centre was monitoring the situation which began to unfold at around 8.30am GMT.

Mr Jambon said: "Our thoughts are with the victims of this horrible act. We are in the process of establishing an overview of exactly what happened."

The crisis centre said a security cordon had been set up around the area and urged people to stay away.

"It (terrorism) is one of the questions on the table, but for the moment all scenarios are open," a spokesman for the crisis centre said.

Images on social media showed people scurrying for safety on Liege's central boulevard d'Avroy with shots and sirens being heard in the background.

One video showed two police officers in body armour moving into position.

Prime Minister Charles Michel said his thoughts were with the families of the victims after what he called a "serious incident" but added he would not give further details at this stage.

Theresa May said the UK would stand together with its allies in the fight against terror.

The Prime Minister tweeted: "My thoughts are with the victims of today's cowardly attack in Belgium and their grieving families.

"The UK stands resolute with our Belgian allies against terror."

French President Emmanuel Macron voiced "solidarity" with Belgium, condemning it as a "terrible attack".

Authorities said it was unlikely the terror threat level for Belgium would be raised.

Liege is an industrial city close to the German border in the French-speaking Wallonia region.

It was the scene of a shooting in 2011 when a gunman killed four people and wounded more than 100 before turning the gun on himself.

Belgium has been on high alert since a Brussels-based Islamic State cell was involved in attacks on Paris in 2015 that killed 130 people and Brussels in 2016 in which 32 died.