Updated

A French official says police on the French Riviera found a stash of explosives in the possession of a suspected jihadist who returned home from Syria with apparent aims to carry out an attack.

An official familiar with the case said Wednesday that authorities found 900 grams (2 pounds) of explosives in Mandelieu-La-Napoule near Cannes following the arrest last month of a 23-year-old man identified as Ibrahim B. The explosives consisted of triacetone triperoxide, or TATP — the same substance used in the 2005 London subway and bus bombings.

The official said a possible target and timing of an attack weren't immediately known.

European officials worry that hundreds of Western jihadists in Syria fighting President Bashar Assad's regime could return home with skills and plans to carry out attacks.