Belgian police have blocked off a residential area in the Belgian city of Ghent following reports that four armed men were seen entering an apartment building.
The Associated Press reported that local police have not yet determined if it is a hostage situation.
Federal police spokeswoman Annemie Serlippens said there did not appear to be a link to terrorism or politics.
"This isn't the same sort of incident as the events in Sydney," she told the BBC, referring to the hours long siege of a cafe in downtown Sydney, Australia.
The BBC quoted the De Standaard website that the head of Ghent police Filip Rasschaert said law enforcement was treading carefully in case there was a hostage.
"They have all they need to bring a successful end to a hostage-taking," he said according to the BBC.
The AP quoted Belgian media which reported that a hostage incident in Ghent two months ago was linked to extortion.