Local officials say attacks that killed dozens of people in the northern Afghan province of Sari Pul were carried out by Taliban fighters who teamed up with a commander claiming allegiance to the Islamic State (IS) militant group.
Up to 50 people, including women and children, were killed after the militants seized control of the Mirzawalang area in the Sayad district on August 5 following two days of intense gunbattles with security forces, Afghan officials said.
Mirzawalang is in a remote part of the country where both Taliban and IS fighters have a presence.
"According to our credible information, 50 people have been killed," Sharif Aminyar, the district governor of Sayad, said on August 6.
Aminyar added that 18 of the people killed had been members of the Afghan local police and other local government-backed militias, while the rest were civilians.
Mohammad Noor Rahmani, head of the provincial council, said at least 25 civilians were also missing.
Aminyar said that "it was a joint Daesh and Taliban operation," using the Arabic acronym for Islamic State.
"The Taliban were led by Mullah Nader and Daesh was led by Sher Mohammed Ghazanfar," he said.
Zabihullah Mujahid, a spokesman for the Taliban, denied any cooperation with IS in the operation.
He said the Taliban carried out the attack on Mirzawalang village, but he denied it was involved in the civilian deaths and abductions.
"Ghazanfar is not Daesh -- he is our commander in Sari Pul, a very active commander, and he is under our command, our flag," he said. "He has allegiance with us."
In the past, the Taliban and IS have fought battles against each other. A combining of their forces, if confirmed, would present a worrying development for the U.S.-backed Afghan government.
General John W. Nicholson Jr., commander of U.S. and NATO forces in Afghanistan, warned of the potential dangers in April.
“One of the things we are concerned about here in Afghanistan, the reason we think that the entire world needs to be focused on Afghanistan, is the potential for convergence among the various terrorist groups in this area,” he told a news conference at the time.