MARSEILLE (Reuters) - A suspected arsonist was placed under formal investigation and held in custody in France on Friday on suspicion of having started several fires on the French Riviera, a judicial source said.

The 19-year-old man has admitted causing about ten fires that destroyed more than one hundred hectares and about ten vehicles in the municipalities of Istres and Fos-sur-Mer in June, the source told Reuters.

If convicted, he could face up 15 years in jail.

The southeastern part of France has been severely hit by forest fires this summer and thousands of hectares were devastated at the end of July.

No deaths have been reported so far.