At least three civilians including two schoolchildren died and six were injured following a NATO airstrike in Kunar province in eastern Afghanistan, regional governor Said Fazlulla Wakhidi said on Tuesday.

The airstrike took place in the Vatapur district late on Monday night, the governor said, after an attack by Taliban fighters on an American military base and battle with NATO troops. A grenade fired by one of the Taliban hit a residential building in the attack, wounding five Afghan civilians.

NATO attack helicopters carried out an airstrike in response, but cannon shells from a helicopter hit a school, killing the civilians.

At least 1,462 civilians have been killed by fighting in Afghanistan in the first six months of this year, 14 percent more than the same period last year, according to UN human rights officials.