Specialist Charles Graner was pictured over the body of a dead prisoner (AP Photo/ABC News)

New pictures have emerged showing two US guards at Baghdad's Abu Ghraib prison posing with the body of a detainee who died in custody.

In the pictures, the Americans are smiling and giving the thumbs-up sign over the corpse.

Both are among seven former US guards at Abu Ghraib facing courts martial for allegedly abusing prisoners.

Senior US generals have insisted that the abuse of Iraqi prisoners was not officially sanctioned.

ln pictures: Prisoner abuse Warning: You may find some of these pictures disturbing

The new pictures emerged as the US denied allegations that its forces in Iraq had killed dozens of civilians by mistakenly bombing a wedding party near the Syrian border.

A US spokesman confirmed 40 people had been killed in the area, but said the US had targeted a safe house used by foreign fighters.

Later on Thursday, President George W Bush is to meet senior Republicans to try - correspondents say - to convince them that the situation in Iraq is not out of control.

Opinion polls suggest large numbers of Americans do not feel that things are going well.

Abuse has happened in Afghanistan, it's happened in Iraq, it's happened at various places   Gen Abizaid   US media sceptical on trial

Wednesday saw an American soldier, Jeremy Sivits, sentenced to a year in prison after admitting to a US court martial that he abused inmates at Abu Ghraib and photographed them.

But some of the president's closest supporters have been claiming that the media are responsible for painting an overly gloomy picture of events in Iraq.

'Sense of gloom'

The two new pictures were broadcast by the American television network ABC.

The soldiers pictured are Sabrina Harman and Charles Graner.

The BBC's Justin Webb in Washington says the new pictures will add to the sense of gloom in the US capital - a mood which was captured in comments to the Senate Foreign Relations Committee by the former head of US Central Command, General Joseph Hoare.

Harman is also facing trial on abuse charges (AP Photo/ABC News)

"I believe we are absolutely on the brink of failure," he said. "We are looking into the abyss."

A US Senate hearing on Wednesday heard from General John Abizaid - who is in charge of military operations in Iraq and Afghanistan - that abuse had taken place in both countries.

Also questioned were the commander of US forces in Iraq, Lieutenant General Ricardo Sanchez, and Iraq prisons chief Major General Geoffrey Miller.

Gen Miller acknowledged that there had been isolated cases of abuse at the US military base in Guantanamo Bay, Cuba, where he used to be the commander.

But he strongly denied that any of the abuses in Guantanamo Bay or Iraq were officially sanctioned.