Blasts at French petrochemical plant appear 'malicious'

Two explosions which started fires at a petrochemical plant in southern France early Tuesday are believed to have been the result of a "malicious act", sources said.

Police said no-one was injured in the explosions that happened in Berre-l'Etang near Marseille-Marignane airport at 3:00 am (0100 GMT).

Two tanks full of petrol and naphtha -- a flammable liquid distilled from petroleum -- caught fire after the blasts and a thick cloud of smoke was visible several kilometres away.

The fires burnt for hours but by late morning Tuesday, they had been extinguished, local authorities said.

The plant is operated by chemical firm LyondellBasell, which said the fires were not toxic.

A source close to the case said investigators believed the explosions were the result of "a malicious act."

"The probability that these two fires in tanks 500 metres (1,640 feet) apart could be accidental is very low. Investigators are leaning towards the theory of a voluntary act," another informed source said.

Police, with gas masks hanging around their neck, set up road blocks to stop anyone from getting near the site, and more than 100 firefighters were in action at the scene.