US forces killed two Islamic State group "officials" in an overnight raid in eastern Syria, US Central Command said on Sunday.
The forces "conducted a successful helicopter raid in eastern Syria at 2:57 am (2357 GMT)... killing two ISIS officials," CENTCOM said in a statement, using an alternative acronym for IS and without providing a more specific location.
It identified one of those killed as "Anas", an IS "Syria province official" who was involved in "plotting and facilitation operations in eastern Syria", according to the statement.
The Syrian Observatory for Human Rights war monitor said it was the "most prominent" anti-IS operation for at least three weeks.
Observatory chief Rami Abdel Rahman said the anti-terrorism unit of the Kurdish-led Syrian Democratic Forces (SDF) also took part in Sunday's operation, identifying the village of Al-Zor in eastern Deir Ezzor province as the target area.
CENTCOM called it a "unilateral operation", adding that "initial assessments indicate no civilians were killed or injured".
The United States supports the SDF, which is the Kurds' de facto army in northern Syria and led the battle that dislodged IS from the last scraps of its Syrian territory in 2019.
Hundreds of American troops remain in Syria as part of an international coalition fighting IS remnants.
Turkey said it launched strikes on Kurdish fighters' positions in northern Syria and Iraq on November 20 after a deadly bombing in Istanbul last month that it blames on Kurdish groups.
Ankara says it has struck positions of the Syrian Kurdish People's Protection Units (YPG), which dominate the SDF but which Ankara sees as an offshoot of the outlawed Kurdistan Workers' Party (PKK).
Turkish President Recep Tayyip Erdogan on Sunday told Russian counterpart Vladimir Putin that it was imperative the Kremlin "clear" Kurdish forces from the border area of northern Syria.
The SDF has warned that a threatened Turkish ground incursion would jeopardise the fight against IS.