NATO-led forces in Afghanistan said on Monday they had mistakenly killed a group of children in an air strike that has enraged the government, and said their deaths may have been linked to an anti-insurgent operation in the area.

The air strike took place last Wednesday near the village of Giawa, in eastern Kapisa province, and followed similar bombings that have stoked tension between the government and NATO over a civilian death toll that has risen annually for five years.

The children were killed as NATO aircraft and ground forces attacked insurgents on open ground in the Najrab district of Kapisa, said Brigadier General Carsten Jacobson, a spokesman for NATO's 130,000-strong International Security Assistance Force (ISAF).

"At this point in our assessment we can neither confirm nor deny, with reasonable assurance, a direct link to the engagement. Nonetheless, any death of innocents not associated with armed conflict is a tragedy," Jacobson said.

Afghan government officials showed gruesome photographs of eight dead boys, and said seven of them had been aged between six and 14, while one had been around 18 years old. They were bombed twice while herding sheep in heavy snow and lighting a fire to keep warm, they said.

"Where were the rights for these children who have been violated? Did they have rights or not? Did they have rights to live as part of the world community?" said Mohammad Tahir Safi, a member of parliament sent by President Hamid Karzai to investigate the air strike.

French soldiers in the area were denied permission to call in air support for an attack north of an area called Ahmad Bik hill, Safi said, citing Afghan security officials in Kapisa, northeast of Kabul.
Despite that, the air strike was launched, Safi said.

Jacobson said the anti-insurgent operation had been carried out according to NATO rules on air strikes, which have been tightened and reviewed under pressure from Karzai and the government.
Karzai's popularity is damaged by civilian deaths and he has repeatedly urged NATO forces to stop killing villagers.

The Afghan government said the Kapisa attack, and a recent air strike in the eastern province of Kunar that killed seven civilians, had people in both provinces demanding curbs on NATO operations ahead of the planned departure of foreign combat troops by the end of 2014.

Civilian deaths rise again
The United Nations said this month the number of civilians killed and wounded in the Afghan war had risen for the fifth year in a row, from 2,790 civilian deaths in 2010 to 3,021 in 2011.

Most deaths were caused by insurgents, the United Nations said, but civilian deaths due to NATO air strikes also rose nine percent to 187. Air strikes were the main reason behind civilian deaths caused by NATO.

Separately, two 10-year-old would-be suicide bombers were captured on Sunday in Kandahar province in the south, just months after being pardoned by Karzai, provincial spokesman Zalmai Ayubi said.

The boys, pardoned with 18 others last August, had been carrying suicide bomb vests when they were arrested with three other militants planning an attack on Afghan and NATO forces, Ayubi said.

Officials told Afghanistan's Tolo TV that the pair had gone to Pakistan after their release, but were sent back to Afghanistan by insurgents taking sanctuary there after being re-trained and told that US troops 'will not be able to hit you'.

Afghanistan's government has been battling to stop the recruitment of child soldiers by the insurgents as the war drags into an eleventh year. Billboards in the capital, Kabul, encourage families to avoid involvement in conflict.