US-trained Syrian rebels believe captured by militants — source

WASHINGTON — The United States believes that at least five Syrian rebels who were trained by the US military have been captured by suspected members of Syria's Al Qaeda affiliate, Al Nusra Front, a US official said on Tuesday, speaking on condition of anonymity.

If confirmed, the capture of the US-trained fighters would be another blow to the US military's still fledgling programme to deploy local forces to counter Daesh militants inside Syria, supporting them with US-led coalition air strikes.

US President Barack Obama has ruled out deploying American ground forces to battle the group.

Details surrounding the capture of the US-trained fighters were still unclear, including the precise timing.

Two US defence officials said it took place in the days after a Friday attack by suspected Al Nusra Front fighters against some of the US-trained Syrian rebels and the Western-aligned Syrian opposition force they hailed from, known as Division 30.

Reuters has reported that one of the US-trained Syrian fighters was killed in Friday's attack. It was the first known battlefield casualty of the US military's programme, which was launched in May and only fielded its first recruits in recent weeks.

The US military's training programme has been challenged from the start, with many candidates being declared ineligible and some even dropping out.

Obama's requirement that they target militants from Daesh has sidelined huge segments of the Syrian opposition, which is focusing instead on battling Syrian government forces.

Only around 60 have been deployed to the battlefield so far.

The Pentagon, which had last week offered assurances that none of the US-trained Syrian fighters had been captured, declined to publicly provide those assurances on Monday. It also would not comment on the status of the US-trained fighters.

"We're not in a position to be able to provide you tactical details," spokesman Captain Jeff Davis told a news briefing, while acknowledging "developments" since the Pentagon's assurances last week.

One of the most powerful insurgent groups in northern Syria, Al Nusra Front has a record of crushing rebel groups that have received support from Western states, including the Hazzm movement that collapsed earlier this year.

Davis said the United States remained committed to defending the Syrian fighters, including against the threat from Al Nusra Front, noting that the United States used air strikes to help repel the attack by suspected Al Nusra Front fighters on Friday.

"The Al Nusra Front has publicly declared itself an Al Qaeda affiliate... and we remain committed to working with our partners in the region to counter the threat," Davis said.