Afghan President Hamid Karzai has ordered an investigation into a coalition airstrike that local officials in the eastern part of the country say killed a family of eight.

Earlier Sunday, a government spokesman for Paktia Province, Rohullah Samoon, told VOA a coalition airstrike killed a man, his wife and six children overnight in the Gerda Serai district. He said according to his information, the man was not linked to any insurgent group or any anti-government activities.

A coalition spokeswoman confirmed that NATO returned fire and requested close air support during clashes with insurgents, but she said they are investigating whether civilians died in the fighting.

Civilian casualties have been a source of friction between President Karzai's government and the international coalition in Afghanistan. A NATO airstrike in northeastern Kapisa province earlier this year killed eight children.

Last year, Afghanistan saw a sharp rise in civilian deaths, with more than three-quarters of the 3,000 fatalities blamed on insurgent attacks and 14 percent attributed to international and Afghan forces.

Earlier this month, U.N. special representative to Afghanistan Jan Kubis said civilian casualties are 20 percent lower in the first four months of 2012, compared to the same period last year. Kubis said insurgent attacks, including suicide bombings, still cause the majority of civilian deaths.