The group targeted has refused to negotiate over a French hostage kidnapped in the region in April, the French defence ministry said. It said the raid was aimed at stopping an attack against Mauritania, according to the BBC.

Spanish reports said a raid to free the hostage, Michel Germaneau, had failed. Al-Qaeda in the Islamic Maghreb (AQIM) had threatened to kill Mr Germaneau.

It was not immediately clear where the raid had taken place, though Reuters news agency cited Malian officials saying that military aircraft had been coming and going and shots had been fired in the north of Mali.

Western nations have been training security forces in West and North Africa to help them tackle AQIM but they do not normally admit being involved in operations.