LONDON — An international court ruled on Thursday that its chief prosecutor could open an investigation into allegations of war crimes in Afghanistan, including any that may have been committed by Americans, setting up a potential showdown with Washington.
The ruling by the International Criminal Court in The Hague is likely to draw a stark rebuke from the United States, which does not recognize the court’s jurisdiction. Washington revoked the visa of the body’s chief prosecutor, Fatou Bensouda, last year after she signaled her intentions to pursue the case.
The ruling on Thursday is the first involving Americans by the court, which was established more than 15 years ago to seek justice for victims of war crimes, crimes against humanity and genocide.
Having spent years collecting information on the Afghan war, Ms. Bensouda requested permission to open an investigation into claims of war crimes and crimes against humanity attributed to United States military and intelligence forces, the Taliban, and Afghan forces.
The prosecutor has said that the court had enough information to prove that U.S. forces had “committed acts of torture, cruel treatment, outrages upon personal dignity, rape and sexual violence” in Afghanistan in 2003 and 2004, and later in clandestine C.I.A. facilities in Poland, Romania and Lithuania.
The wide-ranging investigation would also look into allegations against the Afghan government forces, which are accused of torturing prisoners; as well as those against the Taliban and antigovernment forces.
The United Nations’ mission in Afghanistan has documented the killings of more than 17,000 civilians by the Taliban since 2009, including nearly 7,000 targeted killings.
A pretrial chamber at the court rejected Ms. Bensouda’s request in April, arguing that a successful prosecution was unlikely because the United States and the Afghan government, which has set up its own investigation unit, were unlikely to cooperate.
Prosecutors appealed the ruling, and appeals judges at the court ruled on Thursday that the investigation could proceed.
“The prosecutor is authorized to commence an investigation into alleged crimes committed on the territory of Afghanistan since May 1, 2003, as well as other alleged crimes that have a nexus to the armed conflict in Afghanistan,” said Piotr Hofmanski, the presiding judge of the appeals panel.
The ruling came days after the United States signed a deal with the Taliban to withdraw U.S. troops from Afghanistan after nearly two decades of conflict.
This is a developing story. Please check back for updates.