The UN cultural organisation UNESCO on Thursday listed Mali's legendary town of Timbuktu as endangered world heritage because of the deadly unrest hitting the West African nation.

UNESCO said the decision to place both the town and the nearby Tomb of Askia on its List of World Heritage in Danger "aims to raise cooperation and support for the sites threatened by the armed conflict in the region."

The world's main watchdog over the safety of some of history's greatest treasures and most threatened cultural exhibits designated the iconic town -- once a trading mecca and hub of scholarly studies -- a heritage site in 1988.

The Tomb of Askia for its part is a towering pyramidal structure erected out of mud more than 500 years ago to commemorate the burial site of a ruler who created an empire around the powerful Niger River.

The tomb is located in Gao -- a town that in recent weeks has been held both by Islamist gunmen with links to Al-Qaeda and a group of Tuareg rebels who also oppose the Mali state.

Tuareg rebels spearheaded the takeover of the north when a March 22 coup in the capital Bamako left the country in chaos. They were soon joined by the Ansar Dine Islamist rebels who have since taken the upper hand.

Tensions have been running high between the two rebel groups because of their differing objectives. Deadly clashes in the resulting fight for supremacy have made Gao into a focal point of unrest.

Islamists claimed control of Gao on Wednesday after fierce clashes with Tuareg separatists left at least 21 people dead.

UNESCO's World Heritage Committee said during its meeting in Russia's second city of Saint Petersburg that both Timbuktu and the tomb were now in danger of being looted.

It called on Mali's neighbours "to do all in their power to prevent the trafficking in cultural objects from these sites" and encouraged stronger cooperation in the region.

"There is concern that such objects, notably important ancient manuscripts, be looted and smuggled abroad by unscrupulous dealers," UNESCO said in a statement.

Fighters from Al-Qaeda in the Islamic Maghreb have been accused of destroying the tomb of St Sidi Amar after taking over Timbuktu in late March.

Fifteen other holy tombs and 300,000 Muslim manuscripts are now at risk in Timbuktu and Gao, experts said last month.

The annual UNESCO committee meeting has already produced some surprise decisions and been torn by diplomatic wrangling linked to the Middle East conflict and even religious affairs.

The committee on Tuesday proclaimed the British city of Liverpool -- home to the Beatles and passionate football -- in danger because of a controversial docklands redevelopment project.

The designation means Liverpool could lose the prestigious heritage status it gained in 2004 in recognition of it being one of the world's most important trading centres in the 18th and 19th centuries.

"The committee contended that the development will extend the city centre significantly and alter the skyline and profile of the site inscribed on the World Heritage List," UNESCO said.

But the biggest controversy concerns the status of a church marking the traditional birthplace of Jesus -- scene of a bloody hostage crisis during the Palestinian uprising against Israeli in 2002.

The Palestinians are trying to get fast-track approval for the Church of the Nativity in the Israeli-controlled West Bank town of Bethlehem to be added to heritage list.

Israel argues that granting the "emergency basis" status would essentially mean that the United Nations as a world body was backing the Palestinian view that the church was being threatened by the Jewish state's troops.

The three Churches involved -- the Catholic as well as Greek Orthodox and Armenian -- for their part have only given look-warm approval for the idea because the dangers this potentially poses to their own rights on the shrine.

A decision on the ancient Bethlehem church is expected by this weekend.