ISLAMABAD, PAKISTAN - The U.S. military on Friday disputed claims that an overnight counterterrorism airstrike in eastern Afghanistan had caused civilian casualties. The U.S. officials insisted that the victims were militants under surveillance.

The incident took place Thursday evening in the Haska Mina district of Nangarhar province. Local authorities said 16 civilians, including women and children, had been killed in two separate airstrikes.

The district chief, Saaz Wali, told VOA eight of the victims belonged to the same family and were in a vehicle when a U.S. airstrike hit them.

But Bob Purtiman, a spokesman for the American military in Afghanistan, dismissed the official assertions.

"The militants were observed loading weapons into a vehicle and were under surveillance until the vehicle was destroyed by an airstrike," Purtiman said.

He also ruled out the possibility of any collateral damage, saying the strike was conducted in the middle of open terrain and there was "zero chance" of civilian casualties.

"This is the second false claim of civilian casualties in the same district within the last three weeks," Purtiman noted.

He reiterated that U.S. forces take all allegations of civilian casualties seriously and review each case fully, as well as take precautions in a way to minimize harm to Afghan civilians.

Local reports

Local security officials say Afghan forces, backed by U.S. airpower, are conducting counterterrorism operations against Islamic State militants in the district, where Thursday's airstrikes occurred.

Several districts of Nangarhar are infested with IS militants, U.S. and Afghan officials said.

Taliban insurgents also are active in the Afghan province. A spokesman for the Islamist insurgency, Zabihullah Mujahid, claimed that shortly after missiles hit the vehicle, local residents gathered near the site and were targeted and killed by the second airstrike.

The armed conflict in Afghanistan has killed more than 1,700 civilians and wounded many more since the beginning of 2017, according to U.N. documentation of civilian casualties.

Meanwhile, the U.N Assistance Mission in Afghanistan (UNAMA) said it had completed its probe into the killings of dozens of civilians in the northern province of Sar-e-Pul and promised to issue its findings soon.

The massacre of about 50 men, women and children this week took place in the Sayad district. Local officials said Taliban insurgents and Islamic State loyalists jointly carried out the bloodshed.

But the Taliban denied involvement, saying official claims implicating the group were "baseless propaganda" against it.

"We are deeply concerned by the harrowing reports of civilians being killed and atrocities being committed," UNAMA chief Tadamichi Yamamoto said.

UNAMA, however, urged all parties to refrain from exploiting harrowing events for political purposes and before basic facts were established.