French and Malian troops have rounded up about 50 suspected Islamist fighters on an island near north Mali's main town, Gao. French and Algerian experts are carrying out DNA tests on a corpse to confirm suspicions that local Al Qaida high-up Abou Zeid was killed in fighting in the Ifoghas mountains this week.
In an operation Thursday, French and Malian troops swooped on an island near the village of Kadji and detained up to 50 men.
Among those detained were foreigners, mainly from Togo and Burkina Faso, Mali's military says, although local people said that the military leaders were not among the detainees.
Kadji is home to about 6,000 people and several hundred members of an Islamist sect known as Ansar Sunna (Followers of the word of God) lived on the island.
Some residents tipped off the authorities that members of the Mujao armed group had taken refuge on the island, leading to the raid but some people are reported to have fled the area before the raid.
Islamist groups managed to enter Gao and fight pro-government forces there last week.
In Paris the government on Friday refused to confirm that Mohamed Ghedir, alias Abdelhamid Abou Zeid, a leader of Al Qaida in the Islamic Maghreb (Aqim), has been killed in heavy fighting in the Ifoghas mountains this week.
The body of a man resembling Abou Zeid has been flown in secret to Algiers to compare its DNA to that of several members of the radical Islamist's family, intelligence sources have told RFI, confirming reports on Algeria's Ennahar television channel.
This week there has been heavy fighting in the Tirgaghar massif of the Ifoghas mountains, according to Chadian soldiers fighting alongside the French. They say that several dozen Islamist fighters have been killed.
In other news:
West African leaders meeting in Côte d'Ivoire this week called for the international force in Mali to be declared a UN peace-keeping mission;
Nigerian authorities invited the Boko Haram sect to contact the police after the Islamists claimed responsibility for kidnapping seven French nationals in neighbouring Cameroon, leading to speculation that a ransom could be paid;
France's Areva nuclear company said it was tightening up security in Niger, where four of its employees, who are still being held hostage, were kidnapped two years ago and announced that it had mined 3,600 tonnes of uranium there in 2012.