Belgian police sealed off part of a Brussels suburb Thursday, warning residents to stay inside amid media reports that an armed man could be at large.

Associated Press television images showed armed police officers hiding behind buildings and staking out a rooftop in the Forest neighborhood of the Belgian capital.

Masked police, some with automatic weapons, were aiming their guns high at a building near the Place Saint-Denis. A police helicopter flew overhead.

Broadcaster RTL quoted Forest mayor Marc-Jean Ghyssels as saying that police “suspect the presence of an armed man.” The area was sealed off at around 1230 and people were warned to stay in their homes.

Police did not immediately respond to requests for details. There was no immediate indication that Thursday’s incident is terror-related.

A suspect in the deadly Paris attacks in November 2015, Salah Abdeslam, hid in Forest and was caught up in a shootout with police in a nearby apartment.

Belgium recently lowered its threat level after almost two years on high alert. In March 2016 suicide bomb attacks on the Brussels airport and an underground station killed 32 people.

(AP)