Police in Brussels have shot dead a suspect in an anti-terror operation linked to the Paris attacks, after gunmen with assault rifles opened fire and wounded four officers.

The dead person has not been identified but prosecutors said it was not Salah Abdeslam, a key suspect in the November Paris massacre which killed 130 people, and who fled to Brussels after the attacks.

Dozens of security forces in balaclavas armed with submachine guns cordoned off the scene in the Forest neighbourhood, in the south of the Belgian capital, after armed police came under fire during a raid on a house.

"Police were fired at," Eric Van Der Sypt, a spokesman for the Belgian federal prosecutor, told AFP news agency, adding that the search was "linked to the Paris attacks investigation".

"A body was found during a search of a house ... his identity has not been established yet but whatever the case, it is not Salah Abdeslam," Van Der Sypt was later quoted as saying by the Belga news agency.

Brussels officials confirmed a major operation was underway involving police investigating the 13 November shootings when at least one gunman opened fire, though local media reported the manhunt that followed as involving two suspects.

Speaking to reporters in the Ivory Coast, interior minister Bernard Cazeneuve confirmed French special operatives were directly involved in the initial raid when gunfire broke out.

He said the operation involved intelligence linked to the Paris attacks last year, rather than any new terror threat.

Police at the scene where shots were fired during a police search of a house in the suburb of Forest near Brussels, Belgium (Reuters)

Police in Belgium confirmed one or more gunmen were on the run, and officers blocked off roads in the Belgian capital's southern suburb of Forest.

The mayor of the Brussels borough of Forest where the raid took place told Le Soir newspaper that one or more people had barricaded themselves into an apartment and that it was unclear how many others may be on the run.

Eight of the 11 named men charged over the Paris attacks remain in custody, while two others - including prime surviving suspect Saleh Abdeslam - are Belgian nationals.

A police source has reportedly told the AFP news agency that Abdeslam was not the specific target for the raid.

A victim is removed from the scene where shots were fired during a police search of a house in the suburb of Forest near Brussels, Belgium (Reuters)

Police at the scene where shots were fired (Reuters)

With the operation still going on, a police spokesperson said the number of officers injured in the incident had risen from one to three.

The exact circumstances were still unclear, however, including whether the police officers were struck by bullets or injured in another way.

Shots were fired during a counter-terror raid on a house in Forest, Brussels, a spokesman for the federal prosecutors office said.

Belgian media reports described the Forest suburb as close to the Molenbeek neighbourhood, which was home to a number of the Islamist militants confirmed as carrying out the Paris shootings.

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Brussels was placed on a heightened terror alert in the aftermath of the Paris attacks, which saw 130 people killed.

At the time, all schools, universities, metro services and shopping centres closed as Belgian forces hunted for terrorists apparently determined to attack the city.

The lockdown was later lifted, but a heightened terror alert has remained in place in the city.