An airstrike by US-led coalition forces on Friday killed three Afghan villagers who were “heavily armed” but not part of the Taliban insurgency, an Afghan official said.

The governor of eastern Logar province, Neyaz Mohammad Amiri, said the coalition had told local authorities the dead were Taliban insurgents, but that villagers in the remote Ab Josh area disputed that claim, saying the dead were civilians who were protecting their land from nomads.

“The reason the coalition forces fired on them is that they were heavily armed,” Amiri said. “Of course it was a mistake by the coalition forces, but at the same time I blame the villagers for carrying the heavy weapons.”

He said Afghan security forces had been deployed to Ab Josh two days ago to mediate a clash between the villagers and Kuchi nomads, who have a reputation for violence and are often armed with machine guns and heavier weapons.

Security in Logar has deteriorated in recent months as the insurgents have spread across the country and taken control of some remote regions. But the war has also provided cover for local feuds, violent property disputes and organised crime.

The 13-year US-led combat mission in Afghanistan will officially end on New Year’s Eve. Around 13,000 US and Nato troops will remain to provide training and battlefield support.

Elsewhere in the country, a woman and two men, members of the same family, were killed in southern Helmand province when the motorcycle they were sharing hit a roadside bomb, said provincial governor’s spokesman Omar Zawaq.

In neighbouring Kandahar, four members of the intelligence service and a civilian were killed when their vehicle hit a roadside bomb in Dund district, provincial police spokesman Zia Durrani said.