Armed police came under fire as they carried out a daylight search on a property in the quiet suburb, sparking a series of gun battles that wounded four officers and left children trapped in nearby schools.
Brussels gun battle
Belgian Prime Minister Charles Michel said operations were continuing after the gun battle in the southern Brussels suburb of Forest, adding that it was "linked to the attacks in Paris".
"During what was believed to be a routine search, security forces were fired on. That was followed by police operations which are ongoing," Michel told a press conference.
The national security council of key ministers and security officials will meet on Wednesday, he added.
Michel thanked residents for their "composure" as bursts of gunfire erupted in the streets and dozens of heavily-armed police with balaclavas and sub-machineguns sealed off the area.
The dead person had not been identified but prosecutors said it was not Salah Abdeslam, a key suspect in the November 13 killings in Paris claimed by the Islamic State jihadist group, which killed 130 people.
French police said the operation was focused on the associates of one, or several, of 11 people who have been charged in Belgium in connection with the attacks.
"In this operation, one or several people opened fire on the police as they came through the door" of the property in an initial search, the federal prosecutor's office said in a statement.
"One suspect armed with a Kalashnikov-type assault rifle was killed in an assault" by police about three hours later, it said, adding that officers were "actively pursuing investigations, day and night".
'Not Salah Abdeslam'
Eric Van Der Sypt, spokesman for the prosecutor's office, was quoted by the Belga news agency as saying: "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."
A French policewoman, who Justice Minister Koen Geens said had been helping in a joint investigation between French and Belgian police, was among three officers wounded in the initial assault. A fourth was hurt in an exchange of fire.
Abdeslam, 26, who is believed to have played a key role in organising the Paris attacks, fled across the border to Belgium hours after the killings in the French capital and is now one of the most wanted men in Europe.
He was reportedly holed up for three weeks after the Paris attacks in an apartment in the Schaerbeek district in north Brussels, where police found a fingerprint, traces of explosives and possible suicide belts.