DUSHANBE, June 17, 2015, Asia-Plus – Taliban militants yesterday warned the Islamic State (IS) group against spreading its activities to Afghanistan, declaring that the fight against the country’s Western-backed government and the push for strict Islamic rule should be undertaken “under one flag and one leadership.”

International media outlets note that the letter, posted on the Taliban''s official website and addressed to IS leader Abu Bakr al-Baghdadi, claimed the Taliban had achieved much in the 14-year war “against foreign occupiers and their puppet government.”  The letter was attributed to Mullah Akhtar Mansour, acting head of the Taliban leadership council, and the movement''s main link to the reclusive leader Mullah Mohammed Omar, who hasn''t been seen publicly in more than a decade.

The Washington Post notes the underscores the Taliban’s growing concern as it confronts divisions within its ranks.  With its supreme leader, Mohammad Omar, not seen in years, the movement has become increasingly fragmented, divided over strategy and personalities.  IS has seized on the disaffection to recruit Taliban factions into its ranks, offering them funding and attention, according to analysts.

Although its numbers are small and it is battling in remote areas, the IS’s entry has complicated the military and political landscape at a time when most of the international military has left the country and Afghan security forces are struggling to fill the vacuum.  U.S. military leaders have reportedly described the rise of Islamic State-aligned forces in the region as concerning, although those forces are not under the operational or tactical control of Baghdadi.

In recent weeks, the rival militants have battled in several provinces, with the heaviest fighting occurring in Nangahar, on the border with Pakistan.  According to The Washington Post , tribal elders and provincial officials say former Taliban fighters now loyal to the Islamic State control the district of Kot.