Image caption Sgt Bales faces 16 counts of murder

The US soldier accused of killing 16 Afghans and injuring six others could face the death penalty if found guilty of murder, the US Army says.

Staff Sgt Robert Bales will face a court martial on murder and assault charges for a March attack on two villages in southern Afghanistan.

No date has been set for the trial, which will take place at Joint Base Lewis-McChord in Washington state.

No US service member has been executed in more than 50 years.

Sgt Bales faces 16 counts of murder and six counts of attempted murder, as well as charges of assault and using drugs and alcohol while deployed.

Seventeen victims were women or children, and most of them were shot in the head.

Prosecutors say Sgt Bales left his base in Kandahar province, in southern Afghanistan in the early hours of 11 March.

They say he attacked one village, returned to the base and then went out again to attack another nearby compound.

Staff Sgt Robert Bales Aged 39

Two children

Enlisted in 2001

Three previous tours to Iraq

Injured twice Profile: Staff Sgt Robert Bales

A preliminary hearing last week was told that Sgt Bales had a "clear memory" of what had happened, as demonstrated by statements he made a few hours after the incident.

Military prosecutor Maj Rob Steele told the hearing Sgt Bales was conscious of his actions.

Sgt Bales is the only known suspect in the killings - despite repeated Afghan assertions that more than one American was involved.

His defence team has said the government's case is incomplete and has pointed out inconsistencies in pre-trial testimony.

They have not yet said whether they will be using post-traumatic stress as a defence. Sgt Bales served three previous tours in Iraq.

In March, his lawyer said Sgt Bales - whom he described as "a decorated soldier" with an exemplary record before the shooting - saw his friend's leg blown off the day before the killings.