KABUL, Afghanistan — The Fatemiyoun Brigade, a militia of Afghan refugees created by Iran to fight in Syria, held a public symposium in the Iranian city of Mashhad in August 2020. According to online promotional material, the conference was held to highlight the group’s “ultimate aim” to “expel US forces from the region.”

To policymakers and analysts in neighboring Afghanistan, the statement hit far too close to home. The country, which shares a 936-kilometer (582-mile) border with Iran, has been the theater of Washington’s longest-ever foreign incursion.

Then, on Dec. 21, Iran’s Foreign Minister Mohammad Javad Zarif appeared on Afghan television and put forth a disquieting offer to the Afghan government. “The Afghan government, if willing, can regroup [the Fatemiyoun]. … For the fight against Daesh and for the fight against terrorism and for the protection of Afghanistan security,” Zarif told TOLOnews, using the Arabic acronym for the Islamic State (IS).

The offer came after Zarif said the Afghans were in Syria “voluntarily” and that the force numbered no more than 5,000 fighters. Both claims have been heavily reputed by Afghan politicians, families of former fighters and rights groups.