At least ten civilians have been killed in a NATO airstrike on a pickup truck carrying women and children in eastern Afghanistan, Afghan provincial officials said Sunday.

ISAF said 10 enemy forces had been killed in a precision strike in the Wattapur district of Kunar province Saturday, but that they had received no reports of any civilian casualties.

Kunar Police Chief Abdul Habib Sayedkhil told AFP the airstrike hit a pickup truck carrying the women and children as well as four armed insurgents.

"At least four women, four children and two civilian drivers were killed in a NATO airstrike in Wattapur district of Kunar province," he said.

Kunar Provincial Governor Shujaul Mulk Jalala told AFP that 12 civilians -- four women, four children and four men -- were killed, along with four insurgents.

"I can confirm that four armed insurgents belonging to Al-Qaeda were also killed in the airstrike," he said.

Civilians casualties in NATO operations have long been a source of tension between the Afghan government and US-led NATO troops, who are winding down operations as they prepare to withdraw by the end of next year.

President Hamid Karzai has banned his forces requesting NATO strikes during operations in residential areas.

ISAF said it was aware of the allegations and was looking into the incident.

"We can confirm Coalition Forces' conducted a precision strike yesterday... resulting in 10 enemy forces killed," it said in a statement.

"At this time, we have no reports of any civilian casualties in regards to this incident."

Kunar, which borders Pakistan, is a stronghold of the Taliban-led insurgency and is also known to have a strong presence of foreign fighters.

As NATO troops wind down operations and Afghan security forces take charge of security responsibility countrywide, violence in Afghanistan has been on the increase.

Nearly 1,000 civilians were killed and and around 2,000 others were injured in the first half of 2013, according to a UN report, a 23 percent increase from the same period last year.