Dakar: Malian masons on Friday began rebuilding mausoleums in the historic city of Timbuktu destroyed by Islamists during their occupation of the country’s north, the United Nations said.

The earthen tombs of saints, located in the Unesco-listed desert city, were destroyed in July 2012 by militants who considered the local Sufi version of Islam to be idolatrous.

Video footage from the period shows armed militants hacking at the sites with pickaxes. Thousands of ancient manuscripts were also burnt.

“The rehabilitation of Timbuktu’s cultural heritage is critical for the Malian population, for the inhabitants of the city and for the entire world,” said Unesco head Irina Bokova.

Located on an old Saharan trading route that saw salt from the Arab north exchanged for gold and slaves from black Africa to the south, Timbuktu blossomed in the 16th century as an Islamic seat of learning, home to priests, scribes and jurists.

Mali’s President Ebrahim Boubacar Keita is now seeking to rebuild the country after a putsch in March 2012 plunged the country into chaos, allowing Islamists to seize the north and prompting former coloniser France to intervene.

Small pockets of Islamists still operate in the desert, preventing a recovery in the West African country’s once thriving tourism sector.