KABUL: The Taleban Tuesday warned the leader of the Daesh group against waging a parallel insurgency in Afghanistan, after a string of defections and reported clashes with militants loyal to Daesh.

The Middle Eastern group has never formally acknowledged having a presence in Afghanistan but fears are growing that the group is making inroads in the country.

In a letter addressed to Daesh leader Abu Bakr Baghdadi, the Taleban insisted that “war against the Americans and their allies must be conducted under one flag and one leadership.”

“The Islamic Emirate (Taleban) does not consider the multiplicity of jihadi ranks beneficial either for jihad or for Muslims,” said the letter signed by the Taleban deputy leader Mullah Akhtar Mohammad Mansoor.

“Your decisions taken from a distance will result in (the Daesh) losing support of religious scholars, mujahideen... and in order to defend its achievements the Islamic Emirate will be forced to react,” it added.

The letter, published on the Taleban website in Pashto, Urdu, Arabic and Dari, did not elaborate on its threat. The Taleban have seen defections in recent months — with some insurgents apparently adopting the Daesh flag to rebrand themselves as a more lethal force as NATO troops depart.

The two groups are believed to be arrayed against each other in Afghanistan’s restive south, with clashes frequently reported.

Last week, local media reported pitched battles between the Taleban and supporters of Daesh in eastern Afghanistan, with casualties reported on both sides.

Gen. John Campbell, the commander of NATO forces in the country, last month said the Daesh group was recruiting fighters in Afghanistan but they were not yet operational.

There have been fears of Daesh group making inroads in Afghanistan since US-led NATO forces ended their combat mission late last year, after 13 years of fighting the Taleban.

In February, a NATO drone strike killed Mullah Abdul Rauf Khadim, a former Taleban commander and Guantanamo detainee with suspected links to Daesh, in the volatile southern province of Helmand.