They were arrested in connection with firebomb attacks on a bar and a Turkish community room last year in the southwestern French city of Bordeaux and similar incidents in the Mediterranean port city of Marseille.

Members of a youth group named after the jailed Kurdish rebel leader Abdullah Ocalan, nicknamed "Apo," are all in custody while awaiting a possible trial on charges of manufacturing, holding and transporting explosives and destroying property.

Suspected of having links to the outlawed Kurdistan Workers' Party (PKK), they are also accused of financing terrorism and criminal conspiracy in relation with a terrorist enterprise.

A prosecutor will issue a final recommendation in the case in three months, when a judge will decide whether to refer it to trial.

Listed as a terrorist group by Ankara and much of the international community, the PKK has been fighting for self-rule in mainly Kurdish southeast Turkey since 1984. The conflict has claimed more than 37,000 lives.