At least 13 civilians, including women and children, have been killed after their house was hit by mortars during a battle in northern Faryab province, according to Afghan officials.

General Dilawer Shah Dilawer, Faryab's police chief, told the Associated Press news agency on Saturday that three other civilians were wounded after two mortars hit the house on Friday evening.

Dilawer said it was not clear whether the Taliban or Afghan security forces targeted the house in Dawlat Abad district.

He said a delegation has been sent to the area to find out more about the attack.

OPINION: What should the US next move be in Afghanistan?

Confirming the incident, Naimatullah Tofan, Dawlat Abad police chief, told DPA news agency that seven members of one family, except for the father, were killed.

Faryab has witnessed an increase in violence in recent months and both sides have been accused of targeting civilians.

Taliban fighters have escalated attacks throughout the country, challenging a thinly stretched Afghan security forces to fight the ever increasing violence.

There was no immediate comment from the Taliban on the Faryab incident.

In a separate development, US forces in Afghanistan have denied allegations that they killed civilians in an air raid on a vehicle in the eastern province of Nangarhar earlier this week.

Fighters had been observed loading weapons onto the mini-truck, which had been under surveillance until it was destroyed, Bob Purtiman, a spokesman for US forces, said in a statement on Saturday.

The Thursday evening attack had been conducted in the middle of an open field in Haska Mena district with no chance of civilian casualties, he said.

A number of fighters were killed in the attack, the statement said.

Sazolay Shinwari, Haska Meena district's chief, told DPA on Friday that the aerial bombardment had hit a mini-truck, killing 11 civilians, including women and children.

Sohrab Qaderi, a provincial council member from Nangarhar, spoke of 16 dead.

"The area is under the control of Islamic State, but all those killed were civilians who were trying to leave the area," Qaderi said, referring to the Islamic State of Iraq and the Levant (ISIL) group, also known as ISIS.

In a statement, US forces said in the statement."This is the second false claim of civilian casualties in the same district within the last three weeks."

The number of civilian casualties from air raids in Afghanistan is growing.

According to UN figures from July, 1,662 civilians were killed and 3,581 others were wounded in the first six months of 2017.