Ibrahim Boubacar Keita, an ex-prime minister with a reputation for firmness, has won Mali's presidential election.
Mali's army has launched a counter-offensive to retake the central town of Konna seized by rebels, military sources and local residents said.
Mali's Prime Minister Cheick Modibo Diarra has resigned hours after being arrested by soldiers while trying to leave the West African nation.
Residents say insurgents are besieging Timbuktu as they take their fight for a homeland for the nomadic Tuareg to one of the last government holdouts.
Mali's army has abandoned bases around the northern town of Gao to rebels while the leaders of a coup faced a deadline to start handing back power.
Renegade Malian soldiers have gone on television to declare their seizure of power in protest the government's failure to quell a northern rebellion.
Renegade Mali soldiers claim to have seized the presidential palace and arrested several ministers after a gun battle, in an apparent coup d'etat.
West African presidents tightened the screws on Côte d'Ivoire's Laurent Gbagbo on Saturday, ridding him of an ally at the top of the central bank.
At least 10 civilians and one soldier were killed in northern Mali on Thursday when their vehicles hit landmines planted by suspected Tuareg rebels. The casualties in the north of the Sahel state followed three attacks this week by the Malian rebels in the desolate mountain region near the border with Algeria and Niger.