The US army came under renewed pressure on Wednesday over its conduct in a battle at the weekend in the central Iraqi town of Samarra, as Iran's senior religious leader accused the American forces of "a savage massacre" in which 54 locals were reportedly killed.

The battle, in which US forces attempting to deliver new Iraqi currency to two Samarran banks were ambushed by a small force of insurgents - said by US officials to have been dressed as fighters from Saddam Hussein's fedayeen militia - has led to wildly differing accounts from American military officials and local witnesses.

Hospital officials in Samarra said only eight people were killed, all of them civilians, including one Iranian pilgrim. Samarra is the burial place of two of Shia Islam's most revered imams.

Brigadier General Mark Kimmitt, deputy director of operations for coalition forces in Iraq, said he had spoken about the incident on Wednesday to the commander of the division responsible for security in central Iraq, Major General Ray Odierno, but that no investigation had been sought. "He, at this point, believes he has been given the full truth but wants to close out any questions out there," Brig Gen Kimmitt said.

Saadun Isawi, a police official at Samarra hospital, said the facility had received 54 wounded and that the dead included a 73-year-old Iranian pilgrim to the Imam Hadi shrine, a 10-year-old boy and a female employee at Samarra pharmaceutical plant.

Asked about the discrepancy in the numbers of dead, Brig Gen Kimmitt, who said the figure of 54 killed had been arrived at after debriefing troops involved in the action, added: "I can't imagine why the enemy would want to bring a dead body to a hospital."

US officials were at pains to point out that any Iraqi deaths came only after American troops had been ambushed and that the incident had not been instigated as part of the coalition's recently stepped-up offensive operations. They also said conflicting accounts often existed of firefights but that the first rendition from US soldiers engaged in an attack was usually borne out in final reporting. "I trust the reports of my soldiers," said Brig Gen Kimmitt. "The people that attacked those trucks were attacking not only coalition soldiers but were attacking Iraqis trying to provide money for a restored, restabilised, rebuilt Iraq."

According to the official Iranian news agency, Ayatollah Ali Khamenei, Iran's supreme leader, said "the brutal and arrogant occupiers" had "desecrated" a holy Islamic site. Both the outer perimeter walls of the al-Hadi shrine complex, and the mirrors of the shrine itself were scarred by bullets but it was not clear who had fired them. Locals claimed US soldiers had fired indiscriminately at attackers and civilians alike; an American military official acknowledged that munitions used in the engagement could easily have passed through walls behind combatants.