Islamist extremists have destroyed four mausoleums in Timbuktu, tourism officials say.

Ansar Dine rebels linked to al Qaida in the Islamic Maghreb tore down the mausoleums, which were historic but not included on the United Nations list of World Heritage sites.

The mausoleums housed the remains of Muslim scholars and teachers who are revered by the Timbuktu population.

Since taking control of Timbuktu earlier this year, the Islamists have destroyed seven of the 16 mausoleums listed as world heritage sites. Some date back to the 14th century.

According to many residents, the destruction of the graves is the rebels' reaction to the recent UN resolution calling for an international military intervention to remove the Islamists from northern Mali.