By John Le Fevre

A 44-year-old US Army Sergeant from Sherman, Texas is in custody at Camp Liberty in Baghdad after shooting dead five US servicemen at a combat stress clinic on Monday.

Sergeant John Russell, a member of the 54th Engineering Battalion based in Bramberg, Germany, was disarmed and escorted to the stress clinic early Monday morning but argued with staff and was asked to leave.

It’s not yet clear how the soldier, who was near to completing his third tour of duty in Iraq and has previously served in Bosnia and Kosovo, managed to obtain his escort’s weapon before returning to clinic and beginning a shooting spree that resulted in the death of an Army doctor, a Navy doctor and three enlisted personnel.

Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, said the incident highlighted the need for more help for soldiers dealing with multiple deployments.

Combat stress is an increasing problem in the US military whose resources have been stretched thin over many years fighting in Iraq and Afghanistan resulting in many soldiers completing up to five tours of duty.

The continued redeployment of combat seasoned soldiers is also blamed for almost 150 soldiers suiciding last year.

US President Barrack Obama said he is deeply shocked and saddened by the killings, which followed a similar incident last September when a soldier killed two of his superiors at a base south of Baghdad and another incident in which two officers were killed in Kuwait in 2003.