Iran is directly helping the Taliban in an attempt to destabilise western Afghanistan, Ghor provincial officials told Salaam Times.
The bodies of 42 civilians, including children, were found shot and beheaded in three mass graves in Mirzawalang, Sar-e-Pul Province, officials said.
Only 400 to 600 ISIS militants are left in Afghanistan, says the Ministry of Defence.
The militants beheaded a religious scholar and elders who opposed the group's extremism and banned television 'to keep us ignorant', residents say.
Taliban and ISIS activities disproportionately affect innocent civilians, undermine the country's economy and have nothing to do with Islam, observers say.
'They didn't even spare women or children,' one villager said. 'I buried 10 bodies in one grave.'
A joint group of fighters reportedly entered the town, burned mosques, killed dozens of civilians and mutilated their bodies.
Mourners took to the streets, carrying coffins of their loved ones, in protest of the terrorist group.
With civilians largely bearing the brunt of attacks, Afghan unity is the only viable path to defeat terrorism, officials say.
Afghan security forces evacuated embassy staff and all four attackers were killed, officials say.