An Islamic State flag was found by the body of a gunman shot in a house raid near Brussels, authorities said.
Two suspects escaped during the anti-terrorism raid, which was linked to the Paris attacks.
The presence of French police in Brussels at the time of a raid connected with the Paris terror attacks in November was a "coincidence", a Belgian minister has said.
The unnamed minister told reporters that the raid - which began at 2pm local time (1pm GMT) had not been expected to yield much evidence.
At least one gunman opened fire when officers stormed the apartment building in the Forest district of Belgium's capital city, injuring four officers.
In a news conference, Belgian Prime Minister Charles Michel revealed one of the four injured was a French female police officer - but did not confirm reports that one suspect had been killed and at least two others were on the run.
Two of the four injured officers have now been released from hospital.
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.