Several vehicles were in flames after an explosion rocked the center of Italy's second city Milan, according to reports on Thursday.

The incident appears to have been the result of an accident and there are no known fatalities. Officials said at least one person was injured as a result.

Mayor Giuseppe Sala told reporters the van where the blast originated was carrying oxygen cylinders and that the explosion was not due to terrorism or crime.

What happened?

Witnesses in the city's Porta Romana neighborhood reported the loud explosion at about 11:45 a.m. (09:45 UTC) and saw a plume of black smoke. 

Italy's Corriere Della Sera newspaper cited a witness saying the vehicle was carrying oxygen cylinders. Passers-by said there had been a fire followed by a very strong explosion.

Both the city's mayor as well as fire department officials confirmed the vehicle had been carrying oxygen. The exact cause of the blast is still being investigated.

Only one person has been reported injured so far, with the driver of the van sustaining some injuries, Fire service officer Carlo Cardinali told reporters.

"At the moment, only the driver" had reported injuries, he told journalists at the scene, and he managed to escape with "light burns."

As well as engulfing several cars, local media reported that the fire damaged a pharmacy and apartments in a nearby building.

Footage published by the fire department showed there had been a powerful blast, completely burning down a dozen cars on the street.

The Reuters news agency said that one person had been injured in the blast, but that there were no known fatalities.

"I heard the explosion. I live here. I lost my motorcycle and my car, which were on fire. I went into the building to get my cats, but there was too much smoke," the Italian news agency ANSA quoted a resident as saying.

rs, rc/sms (AFP, dpa, Reuters)