Washington (CNN) -- After months of U.S. military investigations into allegations that U.S. troops were involved in the killing of civilians in Afghanistan, the Army's Criminal Investigation Command has opened a criminal probe into the matter.
The investigation was sparked by evidence gathered in Afghanistan and provided to U.S. officials and the NATO alliance by the International Committee of the Red Cross, said Col. Jane Crichton, a spokeswoman for the NATO-led International Security Assistance Force.
The Red Cross' information was provided to criminal investigators on July 17 and an investigation was opened the same day, she said.
In a written statement, the Red Cross said it heard about the allegations and submitted its concerns to "relevant authorities."
"The ICRC's objectives are purely humanitarian," the statement said. "In accordance with its mandate, the ICRC works to ensure that the safety, physical integrity, dignity and rights of individuals are protected and respected. Our protection policy and activities also aim to prevent disappearances and to ascertain the fate of people whose families are without news of them."
It said it would not comment publicly about the allegations "since these are only discussed bilaterally and confidentially with the relevant authorities."
A spokesman for the investigation unit, known as CID, confirmed its involvement. "CID was notified of the allegations on July 17, 2013, by the Office of the Legal Adviser, HQ, ISAF, Kabul, and then CID opened its investigation that same day," Christopher Grey told CNN.
There was no announcement of the investigation at the time, sources told CNN, and Crichton said she did not know when the Afghan government -- which has complained bitterly about the allegations of U.S. misconduct -- may have been alerted.
Army Green Berets in Afghanistan's Wardak province are alleged to have abused Afghan villagers, and may have been involved with Afghan forces in killing them, a U.S. official told CNN.
In response to CNN queries, U.S. military officials had previously said the matter had been investigated and none of the allegations from local civilians had been substantiated.
"U.S. forces conducted several investigations in response to specific allegations from November 2012 to February 2013," Crichton told CNN on Thursday. "At the time, inquiries found no reliable evidence to substantiate misconduct. However, after those investigations, the ICRC provided new information that was not included in the previous investigations. Therefore, the most prudent course in consideration of that new information was to turn the matter over to professional military investigators."
A senior military official tells CNN that the move will take the investigation out of the hands of those serving in Afghanistan and put it in the independent investigatory jurisdiction of CID.
Much of the new detail is being reported in an article in Rolling Stone.
A U.S. official told CNN the allegations involve an Army Operational Detachment Alpha team, or so-called A-team. These are units that have openly operated in Afghanistan for years -- conducting raids and working with local Afghan forces.
Citing the new, ongoing investigation, officials would not detail the new information. Rolling Stone published photographs, interviews and details of alleged U.S. misconduct, including allegations that U.S. troops were involved with Afghan forces in the killing of civilians in the areas.
The Army's Special Operations Command said it was aware of the allegations, but said any further comment could jeopardize the investigation.