Qatar revealed on Monday it had found 30 bodies of ISIS victims in Syria, in a search carried out on the instructions of US investigators.
The remains of people "believed to have been kidnapped and killed" by ISIS were found in the town of Dabiq which was once controlled by the militants, said Qatar's internal security agency Lekhwiya.
The search came as part of an "international operation carried out in response to an official request submitted by the FBI to Lekhwiya", the security service said in a statement carried by the Qatar News Agency. It said rescuers used "advanced technologies" to hunt for graves.
It did not reveal the identities of the victims. DNA tests will be carried out by Qatari agents before "final results" of the search are announced, the statement added. There was no immediate comment from the US.

Syrian help
The Qatari agency said it carried out its mission "in full co-ordination with the Syrian government", which was said to have provided "everything necessary" to assist the search. A group of rebels led by former Al Qaeda affiliate Hayat Tahrir Al Sham took control of Damascus late last year.
"We obtained the information from ISIS prisoners who told us where the bodies were located," a source at Syria’s Ministry of Interior told The National.
"We don’t know to whom the remains belong. The Qatari and American teams took samples to perform the tests. We don't have any information on their identities," the source added.
ISIS once controlled large parts of Syria but lost Dabiq in 2016 as rival groups fought back in the town near Syria's border with Turkey. The group was declared territorially defeated in 2019.
US journalists James Foley and Steven Sotloff, as well as humanitarian workers Kayla Mueller and Peter Kassig, were among those killed by the group. John Cantlie, a British correspondent, was abducted alongside Mr Foley in 2012 and was last seen alive in propaganda videos in 2016.
Hundreds of bodies have been found buried in mass graves in formerly ISIS-ruled territory in Iraq and Syria. New burial sites have also been found since the fall of the Bashar Al Assad regime in Syria last year.
Qatar's involvement comes as it works with the US on ceasefire talks in Gaza, and holds talks on providing President Donald Trump with a new presidential jet, known as Air Force One. The offer was revealed on the eve of a Middle East tour in which Mr Trump will visit Doha as well as Saudi Arabia and the UAE.

