Forty-two people were killed and some 37 wounded in an airstrike on a hospital run by Medecins Sans Frontieres (Doctors Without Borders) in the Afghan city of Kunduz last year, drawing international condemnation.
The US military had been assisting Afghan forces in their fight against Taliban militants, who had launched an offensive in an effort to capture the city.
On Thursday, the Pentagon issued letters of reprimand to 16 people in question, which will effectively end their careers. However, no criminal charges were leveled against them.
"The investigation concluded that certain personnel failed to comply with the rules of engagement and the law of armed conflict, however, the investigation did not conclude that these failures amounted to a war crime," General Joseph Votel, commander of the US Central Command, told reporters on Friday.
"This was an extreme situation," complicated by war fatigue, Votel added.
"The label 'war crime' is typically reserved for intentional acts - intentional targeting of civilians or intentionally targeting protected objects or locations," Votel said. "Again, the investigation found that the incident resulted from a combination of unintentional human errors, process errors and equipment failures, and that none of the personnel knew they were striking a hospital."
Dozens were killed in the US bombardment of a Doctors Without Borders hospital
An initial report released in November
called the attack an accident, and Gen. John Campbell, then-head of US and NATO forces in Afghanistan, later clarified by saying a series of blunders had led to the strike on the hospital.
'A worrying signal to warring parties'
Doctors Without Borders, however, has
cast doubt on the US military's assertion that the bombing was a mistake. The international charity organization said in a statement Friday that it would like to see an "independent and impartial" investigation, adding that the punishments announced by the US military were inadequate and "out of proportion" to the deaths, injuries and destruction caused by the attack.
"The lack of meaningful accountability sends a worrying signal to warring parties, and is unlikely to act as a deterrent against future violations of the rules of war," the organization said.
Meinie Nicolai, president of Doctors Without Borders, also criticized the report's findings: "The threshold that must be crossed for this deadly incident to amount to a grave breach of international humanitarian law is not whether it was intentional or not," Nicolai said, adding, "[A]rmed groups cannot escape their responsibilities on the battlefield simply by ruling out the intent to attack a protected structure such as a hospital."
Survivors dissatisfied
Survivors and those killed in the US strike have expressed dismay that those responsible for the deaths and injuries will not face criminal charges.
Zabihullah Neyazi, a nurse who lost his left arm, eye and a finger in the attack, said administrative punishment wasn't enough and that a "trial should be in Afghanistan, in our presence, in the presence of the victims' families, so they would be satisfied."
General Joseph Votel expressed "deepest condolences" to the victims' families and survivors, and said that $3,000 (2,622 euros) had been paid for those wounded, and $6,000 for those killed in the airstrike.
