Islamist extremists have set fire to a library containing historic manuscripts as French and Malian forces closed in on Timbuktu.
Mayor Ousmane Halle said that the rebels destroyed many priceless ancient books on culture, science and geography.
Mr Halle said he was alarmed at the destruction.
Ground forces backed by French paratroopers and helicopters took control of Timbuktu’s airport and roads leading to the desert town in an overnight operation.
The move marked the latest inroad by the two-week-old French mission to oust radical Islamists from the northern half of Mali, which they seized more than nine months ago.
Timbuktu, long a hub of Islamic learning, is home to 20,000 manuscripts, some dating back as far as the 12th century. Owners succeeded in removing some to save them, while others have been hidden.
Mr Halle said the rebels “torched all the important ancient manuscripts. The ancient books of geography and science. It is the history of Timbuktu, of its people.”
The Timbuktu operation comes a day after the French announced they had seized the airport and a key bridge in a city east of Timbuktu, Gao, one of the other northern provincial capitals that had been under the grip of radical Islamists.
The French and Malian forces so far have met little resistance from the Islamists, who seized northern Mali in the wake of a military coup in the distant capital of Bamako, in southern Mali.
Timbuktu, which lies on an ancient caravan route, has entranced travellers for centuries, is 600 miles from the capital Bamako. During their rule, the militants have systematically destroyed UNESCO World Heritage sites in Timbuktu.
A spokesman for the al Qaida-linked militants has said that the ancient tombs of Sufi saints were destroyed because they contravened Islam, encouraging Muslims to venerate saints instead of God.
Among the tombs they destroyed is that of Sidi Mahmoudou, a saint who died in 955.