Jalalabad, December 19

Rahman Wali’s younger brother was one of 10 Afghan men forced by Islamic State militants to kneel over bombs buried in the soil in a lush green valley in eastern Nangarhar province. The extremists then detonated the bombs, turning the pastoral countryside into a scene of horror.

The August killings were recorded on camera and posted on social media like so many IS atrocities across the Mideast — reflecting how the Islamic State is exporting its particular brand of cruelty as the group seeks to enlarge its footprint in Afghanistan.

It was through the macabre video that 44-year-old Wali learned the fate of his brother, Rahman Gul, an imam in their remote Shinwar district bordering Pakistan. Gul had been kidnapped weeks earlier, together with his wife and six children who were quickly set free.

After his brother’s death, Wali and his family fled to the provincial capital of Jalalabad, seeking refuge in a makeshift camp with thousands of others who left their homes in the valleys hugging the border to escape what is turning out to be an increasingly vicious war for control of the region between the Taliban and fighters of Afghanistan’s IS affiliate.

Reports of an IS presence in Afghanistan first emerged early this year in southern Helmand province, where recruiters believed to have links to the IS leadership in Syria were killed by a US drone strike in February.

In the summer, extremists pledging allegiance to IS also surfaced in Nangarhar, where they challenged the Taliban in border clashes. After see-sawing between the two groups, four districts — Achin, Nazyan, Bati Kot and Spin Gar — fell under IS

control, according to General John F Campbell, the US commander of American and NATO forces in Afghanistan.

Campbell told The Associated Press in an interview this week that IS loyalists in Afghanistan are now trying to consolidate links to the mothership — the so-called “caliphate” proclaimed on territory IS seized in Syria and Iraq after its blitz there in the summer of 2014.

For the present, IS ambitions for Afghanistan seem focused on setting up what it calls “Khorasan Province”.