Belgian federal police searched a house in a small town south of Brussels on Thursday in what prosecutors told local media was part of investigations into the Islamic State attacks in Paris, adding that no one was detained.
The mayor of Sambreville, Jean-Charles Luperto, also told local media after the operation was over that police had been looking for material evidence rather than suspects.
Federal prosecutors could not be reached for comment.
Brussels remains on high alert after a four-day security lockdown ended on Wednesday. That was prompted by fears of more attacks like the one carried out in Paris on Nov. 13 by French and Belgian militants.
Police are hunting a Brussels man suspected of taking part in the Paris violence, and possible accomplices.
Of five people held in Brussels on terrorism charges, two admit driving Salah Abdeslam, brother of suicide bomber Brahim Abdeslam, back from Paris to Brussels - a six-hour round trip just after the attacks. But they deny any knowledge of the plot.
Two other men are charged with driving Abdeslam around Brussels once he got back. A fifth has not been identified.
Belgium lowers security alert level in Brussels -Belga
Belgium lowered the security threat level in Brussels on Thursday after nearly a week on maximum alert following the Islamic State attacks in Paris, national news agency Belga said.
The reduction to Level 3 - serious - from Level 4 - very serious - brings the capital into line with the rest of the country. The national crisis centre could not immediately be reached for comment.
Brussels mosque powder scare turns out to be false alarm
Firecrews and decontamination teams attended a major mosque in Brussels close to the European Union headquarters on Thursday to investigate a suspect powder that police later said turned out to be flour.
Reuters journalists saw about a dozen emergency vehicles, including police, outside the Islamic and Cultural Centre of Belgium, a large Saudi-established institution including a mosque situated 200 metres (yards) from the European Commission.
A spokeswoman for the fire service said it had taken a call from the mosque from a person saying they believed that they had found anthrax powder, prompting the deployment of specialist crews. A police spokesman later said the substance was flour.
Since the Paris attacks on Nov. 13 by French and Belgian Islamic State militants, there have been reports of threats against mosques used by Belgium's half million Muslims, among them some from an unknown group calling itself Christian State