At least one dead and four injured after explosion at sports centre in Belgium

Mayor Michel Méan says the cause of the blast is still under investigation

Police inspectors survey the damage to the sports complex in Chimay, Belgium after the explosion on Thursday night (AP)

At least one person has been killed and four more have been injured after an explosion ripped through a Belgian sports centre.

Two of those wounded are believed to be in a critical condition in hospital.

The blast occurred in the town of Chimay on the French border shortly after midnight.

Local police chief Pierre Maton said he believed it was a gas explosion rather than a militant attack and an investigation has been launched.

Mayor Michel Méan told Belgian radio station RTBF that a man in his 40s had been killed in the explosion.

He said the accident could have been much worse as a mini-football match was normally played at the centre, known locally as "Le Chalon", every Thursday but had been cancelled on this occasion.

Mr Méan said the cause of the explosion was still being investigated as the building was not connected to gas mains, although bottles of gas were found at the site.

He said: “For now, we do not have evidence to determine the cause of the accident”.

Despite initial reports that suggested at least half the centre had collapsed, an inspection of the damage revealed it was not as bad as previously thought.

Windows were blown out of the two-storey building and one corner of the structure was badly damaged, but there was no major collapse.

Firefighters were seen clearing the rubble and securing the building early on Friday but police said they believe everyone had already been rescued.

Chimay has a population of about 10,000 and is known for its brewing industry.

It comes as the country is on high alert after a string of Islamist attacks throughout Europe in recent months.

Earlier this month, two female police officers were attacked by a man wielding a machete and shouting “Allahu Akbar” in Charleroi around 30 miles from Chimay.

Additional reporting by AP