Mali's constitutional court anointed Ibrahim Boubacar Keita as the country's new leader on Tuesday, confirming he had won the presidential election run-off with an overwhelming 77.6 percent of the vote.

The court said his rival, former finance minister Soumaila Cisse, had attracted 22.4 percent on a turnout of 45.7 percent, confirming the result of the August 11 vote announced provisionally by the interior ministry on Thursday last week.

Cisse said during the election the polls had been marred by fraud but vowed to make no official complaint to the court after conceding defeat in the interests of moving on with process of reuniting conflict-scarred Mali.

Keita, 68, a former prime minister and a veteran of the political scene in Bamako, takes office on September 4 and is charged with leading the west African nation out of a 17-month political crisis sparked by a military coup.

Army officers angry at the level of support they had received to combat a separatist Tuareg rebellion in the north overthrew the democratically-elected government of President Amadou Toumani Toure on March 22, 2012.

In the chaos that followed, the Tuareg seized control of an area larger than France before being ousted by Al-Qaeda-linked groups who imposed a brutal interpretation of Islamic law on the local population, carrying out amputations and executions.

The return to democracy has allowed France to begin withdrawing 4,500 troops it sent in January to oust the Islamists.