"Coalition forces killed 15 terrorists and detained three other suspects during simultaneous raids north of Baquba," the military said in a statement.

But Iraqi police, relatives of those killed and a human rights organisation in Baquba gave an entirely different version of the incident in the confessionally divided province of Diyala northeast of the capital.

They said the victims were all poultry farm workers who had been sleeping in the fields of Bushaheen village in an area known as Al-Salam (peace) when US troops raided the area.

The US military said that US troops came under small arms fire from the rooftop of a house when they arrived at their target.

"The ground force returned fire, killing nine armed terrorists on the rooftop, and an additional two armed terrorists, who were identified firing on coalition forces from next to the building, were killed by coalition aircraft supporting fire," it said.

The military said that a helicopter providing air backup to the troops hit a power line forcing it to make an emergency landing, but that no one on board was hurt.

"Three armed suspects were then killed by another coalition aircraft as they attempted to attack the downed aircraft," it said, adding that another "terrorist" was killed by a US sniper in a separate clash.

US forces then cleared homes in the area detaining "three terrorists" who were "found hiding amidst nine women". They also seized 10 assault rifles, a shotgun, a pistol and a crate of explosives, added the statement.

The military said that Tuesday's raid came after they detained a senior leader of Al-Qaeda in Iraq and three of his accomplices near Baquba the previous day.

Al-Qaeda's leader in Iraq, Abu Musab al-Zarqawi, was killed in a June 7 US air strike on his safe house in the same area north of Baghdad.

The main hospital in Baquba said it received 13 bodies from Bushaheen, most of them killed by gunshots to the head and abdomen. It also admitted four wounded people.

At the village, an AFP correspondent saw 13 graves that had been dug to bury the dead.

Hussam Shamel said he, his three brothers and father were sleeping in the fields with other workers because of the summer heat and fears of theft from the chicken pens when US troops descended on the area.

"I hid and saw them shoot my brother Wissam after he started running," Shamel told AFP.

He said a second brother, Hisham, was also killed in the raid while his father and a third brother were missing.

Shamel and other witnesses said no one in the fields shot at US soldiers.

Pools of blood and shreds of clothing could still be seen at the scene.

Witnesses said that a total of nine people were killed in the fields while four others died when soldiers stormed into surrounding homes.

Iraqi police and Hadi al-Azzawi of a human rights oragnisation in Baquba backed the version of the story given by the villagers adding that 10 people were also detained in the US operation.

All of those killed and detained belong to the Sunni Arab Al-Azza tribe, villagers said.

Diyala province is one of Iraq's fiercest battlegrounds because of its explosive mix of Sunnis and Shiites.

It is the second time since Zarqawi's death that the US military has spoken of killing terrorists in the Baquba area. But Iraqi sources dispute the military's account of the earlier operation too.

On June 12, the US military said it killed seven Al-Qaeda-linked operatives in the village of Hashmiyat in an air strike after US soldiers patrolling the area came under fire.

But witnesses said the firefight was triggered when a guard in the village mistook US soldiers in the distance for gang members and began firing towards them. Two of the dead were children.