The BBC aired video of dead civilians including children that appeared to contradict the US military account of a March operation in the town of Ishaqi north of Baghdad.

US officials said at the time that a militant, two women and a child died when US troops became involved in a firefight after a tip-off that an al-Qaeda supporter was visiting a house in the town.

But the new footage, which the BBC said it obtained from a Sunni Arab group opposed to the US-led coalition, appeared to back an Iraqi police report that US troops rounded up and shot 11 people in the house, including four women and five children.

The video showed several bodies, including those of three children, one of them covered in blood.

The BBC said it was clear from the images that the dead had sustained gunshot wounds and the footage had been cross-checked with other images taken at the time and is believed to be genuine.

The broadcast came with Washington already reeling from accusations that US marines killed 24 civilians in the western town of Haditha last November.

Prime Minister Nuri al-Maliki on Wednesday described the conduct of US troops in that operation as an "odious crime" and called for talks "to redefine the obligations of coalition forces."