(Telegraph) — Islamist rebels in northern Mali smashed four more tombs of ancient Muslim saints in Timbuktu on Sunday as the International Criminal Court warned their campaign of destruction was a war crime.

The hardline Islamists who seized control of Timbuktu along with the rest of northern Mali three months ago, consider the shrines to be idolatrous and have wrecked seven tombs in two days.

Mali’s government and the international community have expressed horror and outrage at the destruction of cultural treasures in the fabled city, an ancient desert crossroads and centre of learning known as the “City of 333 Saints”.

“My message to those involved in these criminal acts is clear: stop the destruction of the religious buildings now,” ICC Chief Prosecutor Fatou Bensouda told AFP in an interview in Dakar.

“This is a war crime which my office has authority to fully investigate.”

On Saturday the Islamists destroyed the tombs of Sidi Mahmoud, Sidi Moctar and Alpha Moya, and on Sunday attacked four more including Cheikh el-Kebir’s mausoleum as residents stood by helplessly.

Crying “Allahu akbar” (God is Greatest), the men carrying chisels and hoes smashed the tombs.