Mali troops battle rebels in northern city of Gao

French and Malian troops have fought running battles with Islamist rebels in the centre of Gao, the main city in northern Mali.

Rebels had been pushed out of the city last month but they launched a surprise attack on Sunday.

They used wooden boats to cross the Niger River on Gao's outskirts and then pushed into the heart of the city.

Thomas Fessy reports.