DUBAI, Dec 13 (Reuters) - U.S. forces carried out a "large airborne operation" near Deir al-Zor in eastern Syria on Monday at dawn, Syrian state news agency SANA said. The American forces landed in the town of Busayra, east of Deir al-Zor, and "kidnapped a number of civilians", it said. There was no independent confirmation of the report. In Washington, the Pentagon said U.S-led coalition forces had carried out an operation with the Syrian Democratic Forces (SDF) in Busayra that killed four Islamic State fighters, including one wearing a suicide vest, but there had been no detentions. It added that there was a separate unilateral operation by the SDF but did not say whether anyone was detained by them. The province of Deir al-Zor, along the Iraqi border, is a strategic supply route for Iranian-backed militias who regularly send reinforcements into Syria to support President Bashar al-Assad against insurgents seeking to topple his family rule. U.S. forces are deployed at a base in the al-Tanf region, south of Deir al-Zor, as part of a combat mission against Islamic State militants who continue to wage a low-level insurgency in Iraq and Syria.