The police crisis center announced that operations were over in Brussels sometime after 11 pm (10 pm GMT) local time.

Unconfirmed reports by DH.de suggest that six suspects were arrested during the operation, with one wounded. Those arrested reportedly did not include Salah Abdeslam, the Paris attack terror suspect.

Belgian news agency RTBF reported that several arrests were made elsewhere, including the detention of one man in the region of Charleroi.

Authorities said they will hold a press conference at 00:30 local time (23:30 Sunday GMT).

Earlier, Belgian Defense Minister Steven Vandeput asked the public on Twitter “not to report their movements on social media” using the hashtag #BrusselsLockdown,

“For safety, please observe radio silence on social media about ongoing police operations,” police press-service posted on Twitter.

Residents in central Brussels were told to stay away from windows, and hotel guests were asked to stay inside.

Several central streets in Brussels were cordoned off, while another “large” police deployment was reported in the Etterbeek municipality near the capital.

“Many people, police asked everyone to leave further apart, no explanation as to why,” a Belgian VRT reporter said on Twitter, posting an image of armed law enforcement in the street.

Helicopters have been seen flying over some areas around Brussels, RTL reported, citing witnesses. Police presence has also been reported in Etterbeek, the media said, adding that the Interior Ministry has asked journalists not to give the precise locations of the areas where special forces are deployed.

Authorities said they will hold a press conference when the operations are finished.

The highest level of alert will remain in effect for Brussels on Monday, Belgium’s prime minister announced on Sunday, saying that there is a threat of coordinated, multiple, Paris-like attacks. Brussels has been at the center of an investigation into the Paris attacks, as several of the assailants came from Belgium, and one of the suspected attackers is believed to have returned.