BRUSSELS - An explosion at a sports centre in the southern Belgian town of Chimay early on Friday killed one person and wounded four others, two of them seriously, Belgium's Crisis Centre said.

"It is probably a gas explosion," an official at the agency said, adding that there was no indication of it being a militant attack.

Local media reported the blast occurred just after midnight (2200 GMT) at a sports centre known as "Le Chalon" in Chimay, close to the French border, when five people were still inside the building. Part of the building was destroyed.

Belgium and France, along with the rest of Europe, have been on high alert after Islamic State attacks in Paris and Brussels over the past year.