US troops have targeted and killed a leading member of the so-called Islamic State (IS) group in a commando raid in Syria, military officials say.
The attack took place near the town of Mayadin in eastern Syria.
Abdurakhmon Uzbeki, who was believed to be from Uzbekistan, is said by the Americans to be a close associate of the IS leader, Abu Bakr al-Baghdadi.
The US says he played a key role in an attack on a night club in Istanbul on New Year's Eve which killed 39 people.
Turkish police arrested Abdulkadir Masharipov, the main suspect in the attack, on 17 January after a huge manhunt.
"It was a ground operation. I think that's all we're willing to say about that," US Central Command spokesman John Thomas said in Washington in relation to Friday's attack.
At any one time there are around 500 members of US special forces in Syria, mainly advising and assisting Kurdish and Arab groups fighting IS.
The Eyes On Events's Gary O'Donoghue in Washington says that they have, on rare occasions, conducted their own operations to target specific individuals.Image copyright Reuters Image caption Abdurakhmon Uzbeki is believed to be a close associate of the IS leader Abu Bakhr al-Baghdadi (pictured above)
An "expeditionary targeting force" has operated inside Iraq and Syria to target senior IS and al-Qaeda leaders since late 2015, ABC reported, but usually details of their operations on the ground are not disclosed.
Mr Thomas was quoted by ABC as saying that the US has "a pretty good record of finding these folks and killing them".