BAMAKO - The Mauritanian Hamada Ould Mohamed Kheirou, presumed leader of an armed Islamist group active in West Africa, has again threatened France with war in a video seen Tuesday by a journalist.

"We again declare war on France, which is hostile to the interests of Islam," Kheirou said in Arabic, wearing dark glasses and with his head wrapped in a turban. "The jihad (holy war) will be exported everywhere it is necessary and for God, we must be ready for anything."

The video also showed images of three Westerners -- a Spanish man and woman and an Italian woman - who were kidnapped late in October in a camp for Sahrawi refugees near Tindouf in southern Algeria.

That kidnapping was claimed by Kheirou's Movement for Unity and Justice in West Africa, which then emerged as a breakaway group from Al-Qaeda in the Islamic Maghreb (AQIM), which originated in Algeria and now has bases in northern Mali.

The last part of the video was concerned with the ideology of the group and its ambitions, particularly "to impose sharia (Islamic law) across the whole of west Africa." Young black fighters were shown calling for "pure and tough" Islam.

Mauritania last week issued an international arrest warrant against Kheirou, also known as Abou Qumqum. The mandate also targetted three other Mauritanians, including Moustapha Ould Limam Chafi, an influential man in west Africa who has notably negotiated the release of Western hostages by AQIM.

All four men are accused of being "influential members" of AQIM, of financing terrorism and of supporting terrorist groups in the Sahel strip of northwest African nations on the southern edge of the Sahara.

This zone is difficult to patrol and monitor and AQIM has carried out many attacks on troops, kidnappings of Westerners and traffic of various kinds, including drugs.

Twelve Europeans, including six French nationals, are currently held hostage in the Sahel.