The Pentagon denied reports Thursday that new graduates of its program to train Syrian rebels had been captured by rivals from an Al-Qaeda affiliate.
The Britain-based Syrian Observatory for Human Rights said earlier that Al-Nusra Front had kidnapped eight members of a US-backed rebel unit.
But Commander Elissa Smith, a Pentagon spokesman, denied that any of those captured were among the fighters who have passed through a Pentagon program to prepare them to fight the Islamic State jihadist group.
"While we will not disclose the names of specific groups involved with the Syria Train and Equip Program, I can confirm that there have been no New Syrian Force personnel captured or detained," she told AFP.
The "New Syrian Force" is the term used in Washington to describe Syrian rebels who have been screened to exclude extremist elements and passed a training course led by US troops.
The first batch of graduates of the $500 million program, reportedly 54-strong, are said to have recently crossed into Syria from Turkey.