A new member of an Islamist group in north Mali attacked and burned a saint's tomb classified as a UNESCO World Heritage Site in Timbuktu, the spokesman for the group said Sunday.

The act threatens to raise tensions that have been building between residents and the Islamists who occupied the city in April, and raises worries that instability could lead to the destruction of historic sites in the fabled town known as an ancient seat of Islamic learning.

"A new member of the Ansar Dine group came to Timbuktu and went to the tomb of Sidi Mahmoud Ben Amar on Friday to tell the faithful praying there that the saints" should not be adored, Sanda Ould Boumama, spokesman for Ansar Dine, told The Associated Press.

Boumama refused to say whether Ansar Dine supported the act or not, and that since the man was a new member it must investigate what happened.

Residents at the scene had earlier described the man who attacked the tomb as a member of al-Qaida in the Islamic Maghreb. Diplomats in Bamako have said Ansar Dine has links with AQIM.

Mahamane Cisse and other witnesses who went to pray at the tomb said that a Mauritanian member of AQIM and some members of his group on Friday tore off the doors of the tomb and burned some items, including a mosquito net on the tomb.

The tomb for Sidi Mahmoud Ben Amar is among 16 cemeteries and mausoleums classified as UNESCO World Heritage Sites in Timbuktu, according to a UNESCO website. The city has 333 tombs for saints.

Timbuktu also has mosques classified as UNESCO World Heritage Sites.

Aghaly Yattara said that one of worshippers at the tomb tried to stop the destruction, but men bound him and put him in the back of their car. He said that they eventually released the man.

Religious leaders have called on the Islamic High Council of Mali to denounce this act, and young residents of Timbuktu say they will stage sit-ins in the coming days so that other tombs of saints are not desecrated, said Kader Kalil Ascofare, the director of radio Bouctou, a local radio station.

Timbuktu has been honored as a UNESCO World Heritage site for its architecture and as a spiritual and intellectual capital for the propagation of Islam on the continent during a golden age that began as early as the 13th century and ended around the 16th century. It remains home to the prestigious Koranic Sankore University and other Islamic schools.

UNESCO warned in early April that fighting could damage the historic outpost in northern Mali, and called on Malian authorities and armed rebels to respect the country's heritage, recalling the obligation of countries to safeguard their heritage in times of war.

Timbuktu is home to a library of ancient, camel-skin bound manuscripts covering science, astrology, medicine, history, theology, grammar and geography.

Tuareg separatist fighters and Islamic militants took advantage of the chaos caused by the coup in Bamako in late March to quickly advance and capture the three main towns in the north of Mali. Mali government forces fled south without putting up any major resistance.

Since, Islamist fighters are asserting control over the Texas-sized northern half of the country. The Islamists, some of whom are foreigners, are imposing strict religious law, setting up a possible showdown with Tuareg nationalist rebels who say they want a secular state and want the foreign fighters gone.

Pictures of unveiled women in Timbuktu have either been torn down or covered over with black paint, according to a member of the Malian parliament for the city. The Islamists have also cut the signal for national TV broadcasts to the city because they consider the women not properly covered and don't approve of the music the station plays.

Islamists have attacked businesses selling alcohol, smashing bottles of beer and spirits, according to residents who say it's no longer possible to buy alcoholic drinks. Islamists have also performed public floggings, according to residents and Human Rights Watch.

In a region where residents generally practice a moderate form of Islam, many are having trouble adapting to the new rules.

Ansar Dine — Arabic for Supporters of Islam — was formed at the end of last year and joined the Tuareg rebel group in chasing government forces out of the north, but Ansar Dine now says that it is against north Mali becoming independent.

Western diplomats in Bamako, the capital, say Ansar Dine has links with AQIM, which has kidnapped Europeans and attacked government forces in Mali and beyond. Senior leaders from AQIM have been seen openly in towns in north Mali since Ansar Dine gained some control of them. Diplomats say that fighters sometimes move between the two groups.

Another group that is less well known than AQIM, and may be a spinoff from that group, is the Movement for Oneness and Jihad in West Africa, which has also been bringing Shariah law to north Mali.

Mali has also been battling insecurity in the capital, Bamako. A group of soldiers toppled Mali's democratically elected president in March. The junta leaders then handed power over to an interim government in April, but have not stepped aside. Last week, some soldiers attempted a countercoup, but all the strategic locations they managed to gain control of were quickly recaptured by forces loyal to the junta leader.

West Africa's regional bloc on Thursday said it would soon deploy forces to Mali. The bloc, known as ECOWAS, has previously said it intends to send about 3,000 troops to Mali to help retrain and re-equip the country's military following the political upheaval. The junta quickly rejected the plan, though, saying not a single foreign soldier would step foot in Mali.