KABUL: Both Taliban insurgents and the US military were to blame for an airstrike a week ago that killed 17 people, including a dozen children, during a fierce battle in eastern Afghanistan, President Hamid Karzai said Saturday.    

Karzai made his comments after an Afghan investigation into the April 6 attack raised the civilian death toll from 11 to 17, including 12 children, four women and one innocent man. An American civilian adviser was also killed during the fighting.

The Afghan report says the US strike occurred after the Afghan intelligence service came under attack by militants during an operation to arrest two insurgent commanders in the Shigal district of Kunar province. The area is a major infiltration route for insurgents from sanctuaries in northwestern Pakistan to Afghanistan.

The US-led coalition has confirmed that it launched airstrikes in Kunar province that day but it has not confirmed civilian casualties, saying the investigation is ongoing.

Afghan forces came under fire with heavy and light weapons as they were about to leave the area. It was in that fighting that the American was killed, causing the Americans to call for air support to move the body from the area at the same time houses believed to be containing suspected insurgents were bombarded for hours from the air, according to the report.

It said most of the houses were made of wood and mud and collapsed under the shock of the airstrikes, causing the deaths.

The death of Afghan civilians caught in crossfire has been a major point of contention between international forces and the Afghan government. Earlier this year, Karzai banned his troops from requesting coalition airstrikes following another deadly airstrike in Kunar.

While he said that airstrikes on residential areas were unacceptable, he also strongly condemned insurgents for taking cover in civilian houses during the battle.

Karzai also ordered government officials to offer immediate help to the families who were harmed in the attack, the statement said, without elaborating.

The investigation was carried out by a government delegation sent from Kabul that worked with 75 tribal elders in the area.

Afghan forces have been increasingly taking the lead in combat operations as international forces move to complete their withdrawal by the end of 2014.

But US and other foreign troops still participate and provide air support as they try to clear areas of insurgents and prepare the Afghans to take control.

In other violence, Taliban militants fired rockets at the coalition-controlled section of the airport Saturday in Jalalabad, 125 kilometers  east of Kabul, damaging a helicopter.

Coalition spokesman Maj Adam Wojack confirmed in an email that the air base came under fire by rockets or mortar shells and said one civilian helicopter was damaged. No coalition aircraft were damaged and no casualties were reported, he added.

The Taliban claimed responsibility for the attack. Taliban spokesman Zabiullah Mujahid said militants fired three rockets at the air base ''and reports show one American helicopter was destroyed and other damage was caused.''