The International Criminal Court's new chief prosecutor said Monday he wants to focus his investigation in Afghanistan on the Taliban and Islamic State-Khorasan (IS-K), and to “deprioritise” alleged war crimes by US forces.

A statement said the request was being made to the court's judges in light of developments since the Taliban movement seized control of Afghanistan in a lightning advance last month.

The ICC had already spent 15 years looking into alleged war crimes in Afghanistan before opening a full investigation last year. That probe was put on hold by the Afghan government, which said it was investigating the crimes itself.

The Hague-based ICC is a court of last resort, intervening only when a member country is unable or unwilling to prosecute war crimes, crimes against humanity or genocide.

The fall of the internationally recognised Afghan government and its replacement by the Taliban represent a “significant change of circumstances”, new prosecutor Karim Khan said in a statement.

The Afghanistan probe's inclusion of alleged US crimes had infuriated Washington.

The administration of former US president Donald Trump imposed sanctions on Khan's predecessor Fatou Bensouda over the issue.

Khan said that he would now narrow his focus in Afghanistan due to the “limited resources” of the ICC as it investigates various situations around the world.

“I have therefore decided to focus my office's investigations in Afghanistan on crimes allegedly committed by the Taliban and the Islamic State-Khorasan Province ( “IS-K “) and to deprioritise other aspects of this investigation,” he said.

This was because of the “gravity, scale and continuing nature of alleged crimes by the Taliban and the Islamic State” and the need to “construct credible cases capable of being proved beyond a reasonable doubt in the courtroom,” Khan said.

The ICC prosecutor specifically mentioned the deadly August 26 attack on Kabul airport claimed by IS-K in which 13 US service members and more than 100 Afghan civilians were killed.

“In relation to those aspects of the investigation that have not been prioritised, my office will remain alive to its evidence preservation responsibilities, to the extent they arise,” he said.

The ICC was set up in 2002 to investigate the world's worst crimes in cases where member states were either unable or unwilling to investigate them themselves.

Former prosecutor Bensouda asked ICC judges to approve a formal investigation into Afghanistan in 2017. Appeals judges ruled in March 2020 that it could go ahead.