DAKAR (Reuters) - Islamist fighters fleeing Mali’s ancient Saharan city of Timbuktu as French and Malian troops closed in set fire to a South African-funded library there containing thousands of priceless manuscripts, the city’s mayor said on Monday.

“The rebels sit fire to the newly-constructed Ahmed Baba Institute built by the South Africans ... this happened four days ago,” Halle Ousmane told Reuters by telephone from Bamako. He said he had received the information from his chief of communications who had travelled south from the city a day ago.

Ousmane was not able to immediately say how much the building had been damaged. French and Malian troops were securing the city on Monday.

The mayor said the Islamist rebels, who had occupied the fabled trading town since a Tuareg-led rebellion captured it on April 1 from government forces, also torched his office and the home of a member of parliament.

The Ahmed Baba Institute, one of several libraries and collections in the city containing fragile ancient documents dating back to the 13th century, is named after a Timbuktu-born contemporary of William Shakespeare and houses more than 20,000 scholarly manuscripts. Some were stored in underground vaults.

Fighters from the Islamist alliance in north Mali, which groups AQIM with Malian Islamist group Ansar Dine and AQIM splinter MUJWA, had also destroyed ancient shrines sacred to moderate Sufi Moslems, provoking international outrage.

They had also applied amputations for thieves and stoning of adulterers under sharia law.