Residents of the Iraqi city of Falluja have disputed an American account of an air attack in which at least 20 people were killed.
US forces say the strike set off secondary explosions
They say women and children were among the dead, and that a second missile strike was aimed at rescuers trying to find victims of the first attack.
US forces say they were targeting members of a network headed by an al-Qaeda leader, Abu Musab al-Zarqawi.
They have not suggested, however, that Zarqawi was caught in the assault.
Falluja residents say two missiles were fired at a poor neighbourhood by a US aircraft at about 0930 local time (0530 GMT) on Saturday.
Pictures from the city showed houses reduced to rubble.
"An American plane hit this house and three others were
damaged. Only body parts are left," a witness told news agency Reuters, as rescuers searched the wreckage for survivors.
"They brought us 22 corpses - children, women and youths," cemetery worker Ahmed Hassan told the agency. Hospital sources have also said women and children were among the dead.
Other witnesses accused the US forces of deliberately trying to kill rescuers with their second strike.
In Baghdad, Brigadier General Mark Kimmitt said the house was being used by fighters loyal to Zarqawi, who Washington blames for a series of suicide bombings and the beheading of the American contractor, Nick Berg, whose death was filmed and broadcast on the internet.
"We have significant evidence that there were members of the Zarqawi network in the house," Brig Gen Kimmitt said.
"Today coalition forces conducted a strike on a known
Zarqawi safehouse in southwest Falluja based on multiple confirmations of actionable intelligence."
The air strike caused "multiple secondary explosions" - evidence of ammunition and roadside bomb materials stored there, he said.
Hundreds of residents of Falluja are believed to have died in April when US forces sealed off the town and tried to wrest control from resistance fighters.
The town has remained relatively calm since, but correspondents say the American military remains frustrated by its failure to rid the town of militants.
Last month, American forces were embroiled in a similar dispute after they bombed a group of people close to the border with Syria.
They insisted they had responded to fire from foreign fighters; Iraqis said it had been a wedding party, and that 40 innocent people were killed.