NATO-led forces in Afghanistan have offered condolences for eight young Afghan men killed in an airstrike last week in the eastern part of the country.

Coalition officials told reporters in Kabul that the aircraft dropped two bombs on the civilians in Kapisa province because they appeared to be adults carrying weapons. Officials at the time considered the group to be an imminent threat to coalition forces in the area.

In a statement, coalition commander U.S. General John Allen expressed condolences, saying his command's mission is to protect Afghan civilians and that he takes “very seriously the loss of every Afghan life.”

A coalition spokesman said “warfare is a very imprecise endeavor” and while “often mistakes are made,” the coalition is “very, very diligent” in trying to avoid civilian casualties.

Afghan President Hamid Karzai condemned the airstrike and ordered U.S. and NATO forces to take more actions to prevent civilian casualties.

Local officials say the dead were between the ages of 6 and 14, along with a mentally ill young man around 18 to 20 years old. A coalition military official said examinations of photographs of the bodies found that most of the victims were around 15 years old, while one victim was older.

The issue of civilian casualties caused by coalition operations has long been a source of tension between President Karzai and NATO.

A United Nations report released earlier this month said more than 3,000 civilians were killed in 2011 — the worst death toll in the decade-long Afghan war.

Officials with the U.N. mission in Afghanistan said insurgents were responsible for 77 percent of the Afghan civilian deaths last year, totaling 2,300 people, while 410 deaths were caused by foreign and local forces, a four percent drop from 2010.