LONDON (REUTERS) - A British soldier saw his platoon sergeant fire automatic rifle rounds into the twitching bodies of two Iraqi gunmen lying on the ground during a battle in 2004, he said in a written witness statement released on Wednesday.

In his evidence to a public inquiry into Iraqi allegations of atrocities by British troops during or after the battle of Danny Boy on May 14, 2004, Mr Duncan Aston also said he had seen a fellow soldier stamp on the head of a dead man.

A private at the time who has since left the army, Mr Aston further described seeing three fellow soldiers punch and kick an Iraqi detainee captured during the firefight, named after a checkpoint near the town of Majar al-Kabir in southern Iraq.

The Al-Sweady Inquiry is investigating a range of allegations, including that British troops captured some Iraqis alive and later executed them at their camp, that they mutilated bodies, and that they tortured detainees. If the inquiry were to confirm the most serious Iraqi allegations, the Danny Boy events would go down as some of the worst atrocities of the Iraq war, inviting comparison with the abuse of prisoners by US troops at Baghdad's Abu Ghraib jail.

The inquiry has no power to prosecute but, depending on its conclusions, military prosecutors could decide to bring charges. Almost all the 200 British military witnesses who are scheduled to give evidence at the inquiry over the coming months deny that any of the alleged crimes happened.

Mr Aston is one of just five "conflicted witnesses" whose accounts differ and may back up some of the Iraqi allegations.

The inquiry took evidence from 60 Iraqi witnesses between March and June and started hearing the military witnesses on Monday. A final report into the events is expected late next year.

In his written statement, released by the inquiry as Mr Aston began giving oral evidence on Wednesday, the former private described a scene during the battle that took place in a ditch where the bodies of six Iraqi gunmen lay on the ground.

He said two of the bodies were twitching and looked as if they were "drifting somewhere between life and death".

Mr Aston said that Mr Paul Kelly, then his platoon sergeant, approached the ditch looking angry and tried to fire at one of the twitching bodies. The weapon did not fire and Mr Kelly ordered Mr Aston to hand over his own weapon, which Mr Aston said he did.

"He put a full magazine of bullets into both bodies that had been twitching, but he also fired into the bodies of the other dead gunmen in the ditch. The bodies of the two twitching gunmen stopped twitching," he said.