The US is to reopen its investigation into an air strike in western Afghanistan last month in response to "new evidence" about civilian casualties.

The Afghan government says 90 civilians, mainly women and children, were killed in the attack on Azizabad, in Herat province, a figure backed by the UN. An initial US inquiry found that up to 35 suspected insurgents and seven civilians died.

But last night the military issued a statement announcing a review, after it emerged that film recorded on mobile phones showed rows of bodies of children and babies in a makeshift morgue.

A western official, speaking on condition of anonymity, said one video showed bodies of "tens of children" lined up. He described the footage as "gruesome".

"In light of emerging evidence pertaining to civilian casualties in the August 22 counter-insurgency operation in the Shindand District, Herat province, I feel it is prudent to request that US Central Command send a general officer to review the US investigation and its findings with respect to this new evidence," said General David McKiernan. "The people of Afghanistan have our commitment to get to the truth."

The initial US inquiry said its forces along with Afghan soldiers took fire from militants while approaching Azizabad that "justified use of well-aimed small-arms fire and close air support to defend the combined force".

