WASHINGTON — United States Special Operations forces carried out a ground raid in Syria this month that killed a militant who was known as “a close associate” of the Islamic State’s leader and who had helped plot a deadly attack on a nightclub in Istanbul on New Year’s Day, the military said on Friday.

American troops killed the insurgent, Abdurakhmon Uzbeki, on April 6 in an operation in Mayadin, Syria. He was targeted for his role in the Islamic State’s external terrorist-attack plotting, said Col. John Thomas, a spokesman for the military’s Central Command.

“He facilitated the movement of ISIS foreign terror fighters and funds,” Colonel Thomas said in a Friday briefing to reporters by telephone from the command’s headquarters in Tampa, Fla., using the acronym for the Islamic State. Colonel Thomas said it took until now to confirm that Mr. Uzbeki was killed in the raid two weeks ago.

In describing Mr. Uzbeki as “a close associate” of Abu Bakr al-Baghdadi, the shadowy leader of the terrorist organization, Colonel Thomas said the militant was “known to interact with him in various ways over time.” Colonel Thomas declined to elaborate.