Bamako - Mali appealed to the United Nations on Sunday to take action after extremists ravaged shrines in the fabled city of Timbuktu which UNESCO has listed as an endangered site.

"Mali exhorts the UN to take concrete steps to stop these crimes against the cultural heritage of my people," Culture and Tourism Minister Diallo Fadima Toure said at UNESCO’s annual meeting in the Russian city of Saint Petersburg.

Islamist militants, swinging pick-axes, destroyed at least three ancient tombs of Muslim saints in a rampage just days after the ancient trading hub was put on UNESCO's List of World Heritage in Danger.

The attacks were reminiscent of the Taliban blowing up the giant Buddhas of the Bamiyan valley in Afghanistan -- an ancient Buddhist shrine on the Silk Road and a world heritage site -- in 2001 after branding them un-Islamic.

Mali's Tuareg MNLA rebels withdrew from Timbuktu on the orders of rival militant group Ansar Dine (defenders of the faith) who has instituted strict Islamic law in several northern cities jointly seized by the groups after a March 22 military coup in Mali.

Residents in the capital Bamako said no fighters from the Tuareg National Movement for the Liberation of Azawad (MNLA) could be seen in the last positions they had occupied around Timbuktu and at the airport.

"Ansar Dine gave them two hours to leave" and they did so, according to witnesses.

The Movement for Oneness and Jihad in West Africa (MUJAO) had carried out patrols all through the night and arrested at least four civilians who were carrying arms, residents of the town reported.

The Tuareg fighters, who spearheaded the late March takeover of northern Mali by various rebel groups, lost their regional headquarters and part of a military camp near the airport in Wednesday's clashes.

Several sources reported a column of vehicles packed with Islamist fighters for Ansar Dine had left for Gao from the town of Kidal, which is under their command.

The fighting in Gao took a heavy toll. Witnesses counted at least 21 bodies around the town.

Two dead still lay in front of the governorate, the former headquarters of the MNLA.

MNLA secretary general Bilal Ag Acherif was wounded and evacuated from Gao to Ouagadougou in Burkina Faso.

"He was mostly hit with shrapnel," a hospital source said.

Witnesses said two former colonels who defected to the rebellion were killed, and many Tuaregs were transferred to Algeria with injuries.

"In total 41 people with bullet wounds were treated in the town hospital which has been supported by the International Committee of the Red Cross since April," the ICRC said in a statement.

The Tuareg have demanded a secular independent state, but have increasingly been pushed aside by the Islamist group Ansar Dine.