Army Staff Sgt. Robert Bales will be charged with 17 counts of murder, assault and a string of other offenses in the massacre of Afghan villagers as they slept, a U.S. official said Thursday.

The charges against Bales include 17 counts of murder, six counts of attempted murder and six counts of aggravated assault as well as dereliction of duty and other violations of military law, the official said on condition of anonymity because the charges had not been announced.

The 38-year-old soldier and father of two, who lives in Lake Tapps, Wash., will be charged with a shooting rampage in two villages near his southern Afghanistan military post in the early hours of March 11, gunning down nine Afghan children and eight adults and burning some of the victims’ bodies.

The charges are to be read to Bales today at the military prison at Fort Leavenworth in Kansas where he has been held since being flown from Afghanistan last week. He faces trial under the Uniform Code of Military Justice.

Military authorities had originally said Bales was suspected in the killings of 16 Afghan villagers, nine children and seven adults. They changed that Thursday to 17, raising the number of adults by one but without explaining how the change came about. It’s possible some of the dead were buried before U.S. military officials arrived at the scene of the carnage. Six Afghans were wounded in the attack.

Bales’ civilian attorney, John Henry Browne, did not immediately respond to telephone and email messages seeking comment on the charges.

The killings were yet another blow to U.S-Afghan relations, following a series of missteps, including the mistaken burning of Qurans, which prompted violent protests and revenge killings of American troops in the war zone.

The brutal shooting rampage also prompted renewed debate in the United States about health care for the troops, who have experienced record suicide rates and high rates of post-traumatic stress and brain injuries during repeated deployments over a decade of the wars in Iraq and Afghanistan.

Bales was on his fourth tour of duty, having served three tours in Iraq, where he suffered a head injury and a foot injury. He was assigned to the 2nd Battalion, 3rd Infantry Regiment of the 3rd Stryker Brigade Combat Team, of the 2nd Infantry Division, which is based at Joint Base Lewis-McChord in Washington.