France has claimed that al-Qaida-linked extremists have been defeated in the key city of Gao in north-eastern Mali.

French troops have encircled a key Malian town to stop radical Islamists from striking closer to the capital, a French official said.

France is tripling the number of troops deployed to Mali to 2,500, part of the massive preparation for a land assault to dislodge Islamist extremists.

More than 15,000 people including Malian military personnel have fled into neighbouring countries since members of the nomadic Tuareg ethnic group launched a new rebellion against the Malian government last month, aid officials say.