Image caption Cpl Morlock (l) and Specialist Wagnon (r) and 10 other infantrymen have been charged

A group of US soldiers murdered a number of Afghan civilians and took body parts as trophies, documents released by military officials allege.

The charging sheets relate to allegations that five US soldiers were involved in the murders of civilians in January, February and May of this year.

A further seven servicemen are accused of a conspiracy to cover up the crimes.

Lawyers for some of the accused have denied the accusations, while the army has yet to begin a review of the cases.

'Appropriate engagements'

In charge sheets obtained from the US Army, Staff Sgt Calvin Gibbs, Cpl Jeremy Morlock, Pte First Class Andrew Holmes, Specialist Michael Wagnon and Specialist Adam Winfield are accused of murdering male Afghan civilians with grenades and firearms.

Other soldiers were accused of stabbing an Afghan corpse, taking or possessing photographs of casualties and beating other men in an effort to keep them from talking to investigators.

The soldiers were attached to the Army's Fifth Stryker brigade, which deployed to Afghanistan last year and has seen heavy fighting around Kandahar. They were based in Washington state.

Army spokeswoman Major Kathleen Turner told the BBC the cases were in a preliminary phase of investigation and military prosecutors had yet to decide whether to move ahead with proceedings.

The BBC's Kevin Connolly in Washington says the legal process is likely to be long and complex.

Among other charges, military prosecutors say Staff Sgt Gibbs possessed finger bones, leg bones and a tooth taken from Afghan corpses, and showed fingers to another soldier and threatened to kill him if he reported drug use to commanding officers.

Staff Sgt Gibbs' lawyer Phillip Stackhouse told the Associated Press news agency his client said the shootings were "appropriate engagements", and he denied any conspiracy to murder Afghans.

The case against the men is built largely around statements by Cpl Morlock, US media report.

But Cpl Morlock's lawyer told the Seattle Times his client's statements were made while he was suffering from concussion, was under the influence of prescription drugs, and was being evacuated.