The United Nation's cultural agency UNESCO has told RFI of an urgent need to preserve the Tomb of Askia in northern Mali before the rainy season starts in June.
The heritage-listed mud pyramid in Gao dates back to the 15th century. It was built by Askia Mohamed, the Emperor of the Songhai empire, after he returned from Mecca and made Islam the empire's official religion.
Lazare Eloundou Assomo, UNESCO's representative in Mali, said the tomb was an "impressive testimony of this cultural tradition where a pyramid could be built only with mud [but looks] so monumental."
UNESCO has just finished an assessment of the damage done to the 17-metre tall structure during the Islamist insurgency in northern Mali.
Unlike in Timbuktu where ancient tombs were specifically targeted by jihadists for being "unIslamic", local heritage in Gao went largely untouched.
Until the insurgency, local residents cared for the Tomb by adding layers of plaster to it every year after the rainy season.
But when the Gao was taken over by jihadists in May 2011, this tradition was interrupted as residents turned their attention to basic survival.
Eloundou says the state of the tomb is "worrying".
"It's very fragile because some of the pillars supporting the roof of the prayer room are really in a bad state of degradation, so if good conservation work is not done before the rainy season, I think it could lead to a very difficult situation," he explains.
He adds major conservation work is require to make the structure waterproof so that it can survive the next rainy season.
"We will be working with local masons who have been maintaining the site, [with support] by the technical assistance of international experts and Malian experts who are specialists in mud architecture."
The tomb was placed on the world heritage list in 2004.