The US military has told the BBC it is investigating an incident in which 11 Iraqi civilians may have been deliberately killed by US troops.
Video footage obtained by the BBC appears to challenge the US account of events in the town of Ishaqi in March.
The US said at the time that four people died during a raid, but Iraqi police said 11 were shot by US troops.
The video evidence comes in the wake of the alleged massacre by US marines of up to 24 Iraqi civilians in Haditha.
The troops are also suspected of covering up the deaths in November 2005.
The Haditha incident and several others are being investigated by the Pentagon, according to US military sources.
The US army has also announced that coalition troops in Iraq are to have ethical training following the alleged incident in Haditha.
However, the BBC's Ian Pannell in Baghdad says the move is likely to be greeted with cynicism by many Iraqis, as the troops have long been accused of deliberately targeting civilians.
The video pictures obtained by the BBC appear to contradict the US account of the events in Ishaqi, about 100km (60 miles) north of Baghdad, on 15 March 2006.
The US authorities said they were involved in a firefight after a tip-off that an al-Qaeda supporter was visiting the house.
According to the Americans, the building collapsed under heavy fire killing four people - a suspect, two women and a child.
But a report filed by Iraqi police accused US troops of rounding up and deliberately shooting 11 people in the house, including five children and four women, before blowing up the building.
The video tape obtained by the BBC shows a number of dead adults and children at the site with what our world affairs editor John Simpson says were clearly gunshot wounds.
The pictures came from a hardline Sunni group opposed to coalition forces.
It has been cross-checked with other images taken at the time of events and is believed to be genuine.