Witnesses heard the knife-wielding attacker screamed "allahu akbar" as he threw himself at two policemen, according to local newspaper La Derniere. The attack took place in front of a city centre police station a short walk from the Belgian capital's Grand place, a world renowned tourist attraction. The attacker wounded one police officer outside the city's main police station on Rue du Marché au Charbon at around 5.30am local time on Tuesday morning, Ilse Van De Keere, a police spokesman, said.
The suspect was shot and wounded by another officer, she added.
Ms Van De Keere said there are no current confirmation of the attack being a terror incident and investigations are going. Police would not confirm witness reports the suspect said "Allahu Akbar" when he attacked.
She said: "A police officer was stabbed and slightly wounded.
"His colleagues retaliated by firing shots at the attack who was subdued."
The police officer was rushed to hospital but she confirmed the attacker's injuries are not life threatening, adding: "It is too early to say now what the motives of the attacker is.
"The investigation is underway."
Belgian justice minister Koen Geens also announced investigators were looking at all possible motivations including links to extremist groups but that there were no clear indications as yet.
According to reports by Belgian news website RTL, the attacker may have recently been sectioned.
Interior minister Jan Jambon wrote on Twitter: "The police are once again the victim of a cowardly attack."
During a radio interview, he said: "The perpetrator is not known in any database."
The suspect was not known to have linked to terrorism but is known to Belgian courts of weapons trafficking, according to La Derniere.
The mayor of Brussels, Philippe Close, wrote on Twitter: "All my support to the police officer injured in the line of duty and the police intervened to neutralise the attacker.
"Every day, police men and women in the country ensure the safety of our fellow citizens and deserve more than ever our respect and support."
Belgium has been under heightened security since the March 2016 attacks at Brussels' airport and subway that left 32 people dead, although the national threat level was reduced to two from three on a four-point scale in January.
French President Emmanuel Macron is due to visit the Brussels district of Molenbeek, home of the ISIS jihadists who carried out the 2015 Paris attacks that left 130 people dead.