The chief prosecutor at the International Criminal Court has said, in a report, that US armed forces and CIA personnel may have committed war crimes by torturing detainees in Afghanistan.
The report could raise the possibility of American citizens being indicted. The US, however, is not a member of the ICC.
"Members of US armed forces appear to have subjected at least 61 detained persons to torture, cruel treatment, outrages upon personal dignity on the territory of Afghanistan between 1 May 2003 and 31 December 2014," according to the report issued by Prosecutor Fatou Bensouda's office on Monday.
The report added that CIA operatives may have subjected at least 27 detainees in Afghanistan, Poland, Romania and Lithuania to "torture, cruel treatment, outrages upon personal dignity and/or rape" between December 2002 and March 2008.
Most of the alleged abuse happened in 2003-2004, the report said.
Bensouda said she will decide "imminently'' whether to seek authorisation to open a full-scale investigation into the matter.
State Department spokeswoman Elizabeth Trudeau, however, said the US does not believe an ICC investigation is "warranted or appropriate".
"The United States is deeply committed to complying with the law of war, and we have a robust national system of investigation and accountability that more than meets international standards," Trudeau said.
A Pentagon spokesman, Navy Captain Jeff Davis, said officials were awaiting more details about the ICC findings before commenting.
Established in 2002, the International Criminal Court is the world's first permanent court set up to prosecute war crimes, crimes against humanity and genocide. More than 120 countries around the world are members, but superpowers, including the United States, Russia and China, have not signed up.
Former US President Bill Clinton signed the Rome treaty that established the court on December 31 2000, but President George W Bush renounced the signature, citing fears that Americans would be unfairly prosecuted for political reasons.