One suspect was “neutralised” during the raid on a house in the Brussels suburb of Forest. It is not clear if the suspect was killed.
A major police operation is under way, with two suspects on the run.
Forest is close to Molenbeek, home to several people involved in November’s Paris attacks.
Parts of the area are in lockdown, with police telling residents to stay indoors. Local media are reporting that there may be more than one fugitive. A helicopter has been flying overhead and police commandos have been deployed.
‘Connected to Paris’
“This operation is connected to the Paris attacks,” a spokesman for Belgium’s federal prosecutor said.
Belgian security forces are still hunting suspects and associates of the Brussels-based militants behind the Islamist attacks in the French capital, in which 130 people were killed.
One of the prime suspects, 26-year-old Salah Abdeslam, from Brussels, is still on the run. He left Paris shortly after his brother blew himself up.
Belgian authorities are holding 10 people who were arrested in the months since the attacks.
Of the 130 dead, 89 were killed at the Bataclan concert venue, where gunmen took hostages before becoming involved in a shoot-out with the police.
Other gun and suicide bomb attacks took place near the Stade France sports stadium and at cafes and restaurants in Paris.
This followed attacks on the French satirical magazine Charlie Hebdo and a kosher supermaket the previous January, in which 17 people died.
Islamic State claimed responsibility for the November attacks, saying they were retaliation for French air strikes in Syria and Iraq.
French President Francois Hollande said the attacks were planned in Syria and organised in Belgium.