At least 20 Afghan civilians, including 12 children, were killed in an airstrike targeting a Taliban commander in the eastern province of Kunar, local officials said.
The strike, against local Taliban commander Sharif Mawiya, was the latest in a series targeting senior insurgents, including the shadow governor of the strategic southern province of Helmand, who was killed on 2 December.
Several Taliban military commanders have been killed this month by Afghan forces, backed by US advisers and air power.
The tactic has raised the risk of civilian casualties and Abdul Latif Fazly, a member of the provincial council, said eight women and 12 children were killed and more than 15 others wounded in the airstrike.
However a spokeswoman for the NATO-led Resolute Support mission denied that there were civilian deaths, although she said some civilians were wounded.
"The Taliban continue to use civilians as shields and barricade themselves inside compounds while engaging the Afghan forces," said Debra Richardson of Resolute Support.
She said US airstrikes were supporting the new Afghan army strategy of targeting the entire Taliban organisation, from low-level fighters to high ranking leaders.
"We have reports over 40 Taliban fighters were killed in the Afghan-led operations, supported by US air strikes in Kunar province," said Ms Richardson.
Kunar governor Abdul Satar Mirzakwal said an operation by Afghan forces in Sheltan district killed 38 Taliban and al Qaeda members, including four foreign nationals, and wounded 12 more.
He said the operation targeted Sharif Mawiya, a commander believed to be a facilitator with Al Qaeda militants.
He said an unknown number of civilians were hit in the strike but had no casualty details.
"We know that a number of civilians, including women and children have been killed but we are sending a fact finding team," he said.
The number of Afghan civilians killed in US and Afghan airstrikes has risen sharply this year as Western-backed forces have stepped up aerial operations with the aim of forcing the Taliban to agree to peace talks.
According to United Nations figures, 313 civilians were killed and 336 wounded in airstrikes by US and Afghan forces in the nine months to the end of September, a 39% increase from the same period in 2017.
Airstrike casualties accounted for eight percent of the total 8,050 civilian casualties during the period.