A knifeman 'released from psychiatric care' has been shot after stabbing a police officer 'while shouting "Allahu Akbar" in Brussels this morning.

The attacker struck outside the Belgian capital's central police station at 5.30am in before a colleague retaliated with gunfire.

Witnesses said they heard the suspect crying 'Allahu Akbar' (God is Greatest) - but police have yet to confirm those claims.

The victim, who was stabbed in the neck, was taken to hospital with non-life threatening injuries while the attacker, who was shot in the chest, was seriously injured.

The attack took place on the second day of a state visit to Belgium by French President Emmanuel Macron with memories of the Paris and Brussels attacks running high. Later today, Macron visits the Brussels district of Molenbeek, home of ISIS jihadists who carried out the 2015 Paris attacks that left 130 people dead.

A knifeman 'released from psychiatric care' has been shot after stabbing a police officer 'while shouting "Allahu Akbar" in Brussels this morning

The attacker struck outside the Belgian capital's central police station at 5.30am in before a colleague retaliated with gunfire

Witnesses said they heard the suspect crying 'Allahu Akbar' (God is Greatest) - but police have yet to confirm those claims

Belgian interior minister Jan Jambon said, 'a priori', the suspect in the 'cowardly attack' was not listed in Belgium's counter-terrorism database.

'Police don't know him as someone who was radicalised or a terrorist. He seems to have been in psychiatric care but was released a while ago,' Jambon told Radio Een, adding that investigations continued.

Witnesses say a man with a knife 'threw himself' at the two police officers in front of the central police station, Le Soir reported.

Police spokeswoman Ilse van de Keere told AFP a police officer was 'stabbed and slightly wounded' and taken to hospital.

'His colleagues retaliated by firing shots at the attacker who was subdued' but whose life is not in danger.

Belgian Interior Minister Jan Jambon said the early morning incident was a 'cowardly act against our policemen'

The victim was taken to hospital with non-life threatening injuries while the attacker was seriously injured

The spokeswoman refused to confirm a local media report that the attacker had shouted 'Allahu Akbar'.

Justice Minister Koen Geens said investigators were looking at all possible motivations including links to extremist groups but there were no clear indications as yet.

Belgium, home to European Union institutions and NATO, has been on alert since suicide bombers killed 32 people at Brussels airport and on the city's metro in 2016, although the national threat level was reduced to two from three on a four-point scale in January.