But the United States is not a party to the ICC, and imposed sanctions against the office of the prosecutor for investigating the role of U.S. forces. Shifting the focus of the probe could help mend the court's relationship with Washington.

A lawyer who represents Afghan victims of suspected U.S. torture in the ICC investigation said the narrowing of its focus was "deeply flawed".

"Allowing powerful states to get away (with) multi-year, multi-continent torture against so many, feeds impunity for all," she said on Twitter.

Judges will now review the request.