Four United States soldiers have been charged with conspiracy to commit murder in connection with the deaths of several detainees in Iraq in early 2007, the US Army says.

The soldiers were charged in Grafenwoehr, Germany, where they are currently serving in the 172nd Infantry Brigade, the army said in a statement.

"The soldiers were charged with conspiracy to commit premeditated murder," the statement said.

"The charges relate to an incident that occurred during April/May 2007 in Baghdad, Iraq, while the soldiers were serving in the 1st Battalion, 18th Infantry," it said.

The statement provided no details on the incident, and army public affairs officers refused to elaborate on what the soldiers were accused of doing.

But a spokesman for the US Army in Europe referred reporters to a separate army statement in January 2008 that said the army was investigating the deaths of several detainees captured during combat operations in 2007 by members of the 2nd Brigade Combat Team, 1st Infantry Division.

The soldiers charged include Staff Sergeant Jess Cunningham, Sergeant Charles Quigley, Specialist Stephen Ribordy, and Specialist Belmor Ramos who are from a mechanised infantry unit that belonged to the 1st Infantry Division.

- AFP