The International Criminal Court prosecutor on Monday said he was seeking approval to resume a war crimes investigation of Afghanistan, focusing on the actions of the Taliban and ISIS-Khorasan.
Prosecutor Karim Khan said the request was being made to the court's judges after developments since the Taliban militants seized control of Afghanistan last month.
Prosecutors previously looked into suspected crimes by US and Afghan government troops.
But Mr Khan, six months into his nine-year tenure, said they would now "deprioritise" that because of a lack of resources, and focus on "the scale and nature of crimes within the jurisdiction of the court".
Afghan human rights activist Horia Mosadiq, who has been helping victims to support the ICC probe for years, called the announcement "an insult to thousands of other victims of crimes by Afghan government forces and US and Nato forces".
The ICC had already spent 15 years looking into war crimes allegations in Afghanistan before opening a full investigation last year.
But that was put on hold by the Afghan government, which said it was investigating the crimes itself.
The ICC in the Hague 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.
Mr Khan said the fall of the internationally recognised Afghan government and its replacement by the Taliban represented a "significant change of circumstances".
"After reviewing matters carefully, I have reached the conclusion that, at this time, there is no longer the prospect of genuine and effective domestic investigations ... within Afghanistan," he said.
The court had found there was a reasonable basis to believe war crimes had been committed between 2003 and 2014.
Among them were suspected mass killings of civilians by the Taliban, suspected torture of prisoners by Afghan authorities and, to a lesser extent, by US forces and the CIA.
But the US is not a party to the ICC, and imposed sanctions against the office of the prosecutor for investigating US troops.
Shifting the focus of the investigation could help to mend the court's relationship with Washington.
"We're pleased to see that the ICC prioritises resources to focus on the greatest of allegations and atrocity crimes," US State Department spokeswoman Jalina Porter said.
A lawyer who represents Afghan victims of suspected US 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.
If approved, the investigation will face an uphill battle to gather evidence, as the Taliban rulers appear unlikely to co-operate in the same way as the governments in place since the militants' last period in power ended in 2001.
The Taliban administration in Kabul could not immediately be reached for comment.
"Early indications suggest that their policies on matters related to criminal justice and other material considerations are unlikely to conform to those adopted since 2002," Mr Khan said in his submission to the court.