(Adds Karzai response)
KUNAR, Afghanistan Feb 13 (Reuters) - A NATO air strike killed 10 Afghan civilians, including five children, in eastern Afghanistan on Wednesday, local officials said, a toll that if confirmed is likely to raise tension between President Hamid Karzai's government and U.S.-led NATO forces.
The strike, in the Shigal district of Kunar province, was condemned by Karzai, who expressed his condolences to the families and announced the deaths would be investigated by Afghan authorities.
NATO's International Security Assistance Force (ISAF) said it was aware of the reports of civilian deaths but could not confirm them.
"Foreign forces carried out the attack by themselves without informing us," Kunar Governor Fazlullah Wahidi told Reuters.
Four Taliban fighters were also killed in the strike and five civilians wounded, he said. The strike occurred in the village of Chawgam and the 10 dead civilians were from two local families, Wahidi said.
In a statement, Karzai confirmed the incident and reiterated his view that air strikes on Afghan villages were not the solution to fighting terrorism.
"In Wednesday's air strike which was carried out by NATO forces, two houses were targeted where 10 civilians including women and children were martyred and four more wounded," the statement said.
There have been tensions between Karzai and his foreign backers following his October comments that the U.S. and its allies should go after those in Pakistan who support terrorism, and not fight the war in Afghan villages.
"We take all allegations of civilian casualties seriously and we are currently assessing the incident to determine more facts," an spokesman for ISAF said.
ISAF regularly states that it has reduced civilian casualties in recent years, and that insurgents such as the Taliban are now responsible for 84 per cent of all such deaths and injuries.
The air strike came within hours of U.S. President Barack Obama's declaration that he would be withdrawing half the U.S. troops in Afghanistan - 34,000 - by the end of this year.
That would be followed by further troop withdrawals next year which would lead to the end of the U.S. war in Afghanistan, he said. (Reporting by Mohammad Anwar and Mirwais Harooni; Writing by Dylan Welch; Editing by Michael Holden)