One grim, eight-minute clip, filmed on a mobile phone in the aftermath of the bombing, shows rows of bodies laid side-by-side in a makeshift morgue. Among them are at least 11 children, many of them toddlers.

The footage handed over to the UN mission in Kabul, shows two long rows of bodies apparently killed in the raid, laid on a mosque floor, awaiting burial.

One video, apparently taken by a mobile phone, is grainy and details, including a precise body count, are difficult to make out. However, there appear to be several dozen bodies, all covered by blankets.

A second video shows three young children wrapped in white shrouds. A fourth child has gruesome head wounds.

General David McKiernan, the US commander of Nato's International Security Assistance Force (ISAF), ordered a fresh investigation led by a Pentagon general, after the footage was released.

The top-level review comes just days after he admitted there were "large discrepancies" among conflicting accounts of the death toll.

American officials claim there were just seven civilians killed, but the UN, the Afghan government, and human rights groups say its closer to 90.

The damning footage was shot by a doctor who visited the morgue, in a building normally used as a mosque, on the morning after the 22 August attack.

At one point a blanket is pulled back to show the grey, lifeless face of an infant. The dead child's head is no bigger than a man's hand. A large section of skull is missing. Women can be heard wailing in the background. One mourner is heard crying for his mother.

Locals said most of the dead were women and children.

The bombs were called in by US Special Forces after their patrol was ambushed in Azizabad, in Herat province, shortly before dawn on 22 August. Officials said they were trying to arrest a suspected Taleban commander.

Days after the attack US officials remained adamant just 30 Taleban insurgents had been killed, including their commander, despite detailed claims by Afghan officials that at least 76 people had been killed, including 50 children.

Four days after the air strike the UN top official in Kabul, Kai Eide, claimed he had "convincing evidence … that some 90 civilians were killed, including 60 children, 15 women and 15 men".

Hamid Karzai, Afghanistan's president, said relations with the US had "worsened" in the wake of the raid, which prompted a grovelling phone call from the US president, George Bush.

It comes amid growing criticism of international troops for failing to curb civilian killings. A Human Rights Watch report, published yesterday, said civilian deaths, as a result of US and Nato air strikes, tripled from 2006 to 2007.

Brad Adams, the group's Asia director, said: "Mistakes by the US and Nato have dramatically decreased public support for the Afghan government and the presence of international forces."

American officials eventually revised their initial body count, on 2 September, but this was still nowhere close to the numbers reported elsewhere. A spokesman said: "The investigation found that between 30 and 35 Taleban militants were killed. In addition five to seven civilians were killed, two civilians were injured and subsequently treated."

Mr Eide summoned Gen McKiernan to his office in Kabul last Friday, to see the evidence for himself.

He was furious that the UN had released such an uncompromising statement condemning the raid.

However, a source close to the ISAF commander revealed he was moved almost to tears when he finally saw the images for himself. "He was shocked and humbled. He left like a little boy," a military aide said.

If the 90 dead are confirmed, it would be the worst incident of "collateral damage" in Afghanistan since the 2001 invasion.