France on Saturday condemned as an "intolerable act" the destruction of Muslim shrines by Islamist militants in the fabled city of Timbuktu in northern Mali.

"France condemns the deliberate destruction of the tombs of Muslim saints in the city of Timbuktu by an Islamist extremist group which controls this city," ministry spokesman Bernard Valero said in a statement.

"We appeal for an end to this violence and this intolerance," he said. "The systematic violation of these places of reverence and prayer, which for centuries have been part of the soul of this famed sub-Saharan city, constitutes an intolerable act."

On Saturday, witnesses and UNESCO officials confirmed that the Islamist militants had destroyed three ancient tombs in Timbuktu just days after the UN cultural body had declared them endangered world heritage sites.