The U.S.-led coalition on Sunday disputed reports that eight civilians, including children, were killed in a NATO airstrike in a remote part of eastern Afghanistan.

Afghan officials said an airstrike Saturday night killed eight members of a family, but a senior NATO official said that so far, there is no evidence of any civilian casualties. The official spoke on condition of anonymity because he was not authorized to disclose the information.

The killing of civilians by foreign forces has been a major irritant in Afghan President Hamid Karzai's relationship with his international partners. He warned earlier this month that civilian casualties could undermine a strategic partnership with the U.S. that is to govern long-term relations after most international troops withdraw by the end of 2014.

Karzai appointed a delegation to travel to Paktia province and determine what happened.

The coalition also said it was working to find out more about the operation that foreign forces were conducting in the province.

NATO also reported that one coalition service member died in a roadside bomb attack Sunday in eastern Afghanistan, and four others were killed in separate bomb attacks Saturday in the south. The coalition did not release their nationalities or any other information about their deaths, which bring to 167 the number of NATO deaths in Afghanistan so far this year.

The British Ministry of Defense said one of its soldiers was killed Saturday in an explosion in the Nahr-e Saraj region of southern Helmand province. The nationalities of the others killed were not released.

Elsewhere Sunday, two civilians were killed when their vehicle struck a roadside bomb in Marjah district of Helmand province in the south, provincial spokesman Daud Ahmadi said.

Frequently, Afghan and coalition officials offer differing accounts of military operations.

In those cases, local residents claim civilians were killed, while the coalition says the victims had been identified as insurgents. Later, if investigations prove that civilians were inadvertently killed, the coalition acknowledges its mistake.

Rohullah Samon, a spokesman for the provincial governor, said Mohammad Shafi, his wife and their six children were killed in the airstrike around 8 p.m. in Suri Khail village of Gurda Saria district.

"Shafi was not a Taliban. He was not in any opposition group against the government. He was a villager," Samon said. "Right now, we are working on this case to find out the ages of their children."

Such attacks damage the civilian population's trust in international troops who have been fighting in the country for more than a decade.

Taliban attacks have killed more civilians than foreign forces, but public anger over the issue is usually directed at the international forces.

Tensions spiked after Afghan officials reported that 18 civilians were killed in four recent airstrikes in Logar, Kapisa, Badghis and Helmand provinces. That led Karzai to issue his warning earlier this month.

"If the lives of Afghan people are not safe, the signing of the strategic partnership has no meaning," Karzai's office said.

Last year was the deadliest on record for civilians in the Afghan war, with 3,021 killed as insurgents ratcheted up violence with suicide attacks and roadside bombs, the United Nations said in its latest report on civilian deaths.

The U.N. attributed 77 percent of the deaths to insurgent attacks and 14 percent to actions by international and Afghan troops. Nine percent of cases were classified as having an unknown cause. The U.N. attributed 187 civilian deaths last year to aerial attacks, an increase of 9 percent over 2010.