The army psychiatrist accused of a shooting rampage last week at a military base in Texas has been charged with 13 counts of premeditated murder.
Major Nidal Hasan will face legal proceedings in a military court.
The 39-year-old has been receiving treatment in hospital after sustaining gunshot wounds and has declined to talk to investigators, his lawyer said.
The dead included 12 soldiers and one civilian, while 42 people were wounded.
CNN said military legal authorities were mulling whether to add a 14th murder charge, because one of the fallen female soldiers was pregnant.
Meanwhile, President Barack Obama has ordered a review of how intelligence agencies handled information they had gathered on the army psychiatrist ahead of his alleged shooting rampage at Fort Hood.
'I directed an immediate review be initiated to determine how any such intelligence was handled, shared, and acted upon within individual departments and agencies and what intelligence was shared with others', Mr Obama said in a statement.
