Ghent: Four armed men have entered an apartment in the western Belgian city of Ghent, and police have blocked off a wide perimeter around the area.

Police on Monday said that two hours in it was still unclear what the intention was, and there was no information available either about the armed men who entered the apartment block or whether they had taken hostages.

By midmorning a big police operation had been set up in the working-class neighbourhood to keep bystanders away from the scene.

Acciording to media reports, local prosecutors have said that there was no indication of any link to terrorism or jihadist group Islamic State.

"This isn't the same sort of incident as the events in Sydney," spokeswoman Annemie Serlippens said.

The head of Ghent police Filip Rasschaert told De Standaard website that they were carrying out the operation carefully because of the potential involvement of a hostage.