A NATO airstrike killed five Afghan civilians, including three children, near the eastern city of Jalalabad on Friday night.
Reuters reports Friday's airstrike came after resistance fighters attacked a joint NATO-Afghan base near a village outside Jalalabad, Nangarhar province.
"Last night around 11:00 pm, five civilians aged between 12 and 20 carrying air guns wanted to go hunting birds some eight kilometers (5 miles) from the center of the city of Jalalabad," provincial police spokesman Hazrat Hussain Mashreqiwal stated. "They were targeted and killed by a foreign forces airstrike."
The office of Afghan president issued a statement condemning the deadly strike.
"President Hamid Karzai strongly condemned the NATO airstrike in which he says five civilians, including three students aged 10, 14 and 16, were killed in eastern Nangarhar province on Friday night," the statement read.
The three students mentioned in the president's statement were brothers.
According to NATO, Afghan and coalition forces responded to the mortar attack with a "precision strike."
"Initial reports indicate there were no civilian casualties," a NATO spokesperson said.
"ISAF (NATO's International Security Assistance Force) takes all allegations of civilian casualties seriously and is working with our Afghan partners to confirm the details," NATO said on Saturday.
Civilian casualties have long been a source of tension between the Afghan government and people and the US-led occupation force that has been operating in the country since just after the September 11, 2001 terrorist attacks on the United States. President Karzai once threatened to turn on the occupiers and join the Taliban if the US-led forces did not reduce the number of civilian casualties.
According to the United Nations, nearly 1,000 Afghan civilians were killed and around 2,000 others were injured in the first half of 2013. The vast majority of these casualties have been caused by the Taliban and associated militants. As many as 19,000 Afghan civilians have been killed since the US-led invasion and occupation began 12 years ago, according to Cost of War.
Coalition-caused civilian casualties have decreased recently, although just last month a NATO airstrike killed 16 civilians, including women and children, in Kunar province. At first, NATO claimed that 10 "enemy forces" had been killed, but an investigation was ordered after commanders were shown images of dead civilians.