A few days after desert gunmen swept out of the Sahara and captured Timbuktu, the city's conquerors broadcast a message over its radio station.

"We are going to welcome some foreigners," inhabitants of this ancient trading centre in northern Mali were told. "Do not be afraid when you see them: We must all welcome them."

A convoy of Land Cruisers duly arrived, laden with bearded fighters clad in sand-coloured turbans and robes. These were not rebels from the local Tuareg tribe, who had claimed credit for the fall of Timbuktu, but international jihadists from across the Muslim world including Algerians, Nigerians, Somalis and Pakistanis. This multinational parade drove home a harsh message: a new state had been born under the effective rule of al-Qaida. Bewildered townspeople, who had seen only Tuareg insurgents up to that point, realized its true significance.