A US marine convicted of war crimes in Iraq has been released from prison pending an appellate court's review of his case.

Sergeant Lawrence Hutchins was sentenced to 11 years in prison for killing an Iraqi civilian in the town of Hamdania in 2006.

But a military appeals court in Washington has ruled that Hutchings did not receive a fair trial, because his lead defense attorney left the case shortly before it went to trial.

The US navy is now appealing that ruling to a higher court; Hutchins will remain free until a verdict is issued, which could take until next year.

"I'm going to be the best Marine I can be today," Hutchins said after his release. "Today is really a surreal experience. I think we had a good judge. ... It's hard to describe exactly what I'm feeling. I'm happy."

Hutchins was convicted of leading his seven-man squad in a plot to kidnap and kill the Iraqi man, whose name was not listed in the charges against Hutchins. The squad placed an AK-47 assault rifle and shovel near the man's body, to make him look like an insurgent planting a bomb.

The other members of Hutchins' squad received short jail sentences, all of them less than 18 months.

Ray Mabus, the secretary of the navy, told a US newspaper last year that he believed Hutchins was the leader of the plot, and that he should serve his full sentence.

Hutchins claims he was not with the squad at the time of the murder.