The armed Islamist group Ansar Dine have forced Tuareg rebels to leave the northwestern Mali town of Timbuktu and its outskirts as tension between the armed factions continue to rise.The Al Qaeda linked armed group declared on Thursday that they had secured full control of Mali’s desert north, a day after pushing their former Tuareg separatist allies out of the town of Gao in a gun battle that killed at least 20 peopleResidents contacted from the capital Bamako on Thursday said no fighters from the Tuareg National Movement for the Liberation of Azawad (MNLA) could be seen in the positions they had earlier occupied around Timbuktu and at the airport."Ansar Dine gave them two hours to leave” and they did so, according to the owner of a hotel that had been closed by the Islamist armed group.The order was given before midday Thursday.No official from Ansar Dine or the MNLA could immediately be contacted.Timbuktu threatenedMeanwhile, the United Nations Education, Scientific and Cultural Organisation (UNESCO) put Timbuktu on the list of endangered World Heritage sites on Thursday at the request of the Malian government, desperate to save the historic richness of its fabled city. Timbuktu has 333 tombs of holy saints among which 16 are classified as UNESCO World Heritage Sites includingthat of Sidi Mahamoud Ben Amar, a learned scholar, considered the most sacred in the city.As they sought to impose the sharia law, the Ansar Dine Islamist group further attacked and burned the tomb of oneof the town’s saints, classified as a UNESCO World Heritage site.Islamist fighters patrolled the streets of Gao and arrested civilians on Thursday after dislodging Tuareg rebels from their positions in the northern Mali town in a day of deadly combat.DislodgedThe 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.Two chiefs of armed Islamist groups were seen in the city Thursday, said a local politician - Mokhtar Belmokhtar of Al-Qaeda in the Islamic Maghreb and Iyad Ag Ghaly, head of Ansar Dine. 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 International Committee of the Red Cross (ICRC) said in a statement.The key cities in the north were seized by Tuareg and Islamist rebels after a March 22 coup in Bamako, but the Islamist armed group quickly took the upper hand and began implementing strict Islamic law in Timbuktu, Kidal and Gao.