A US scheme to train Syrian rebels to fight Islamic State (IS) militants has been branded a total failure after a US general admitted only four or five were still fighting.
Congress approved $500m (£323m) to train and equip around 5,000 rebels as a key plank of US strategy against IS.
But the first 54 graduates were routed by an al-Qaeda affiliate, Gen Lloyd Austin told lawmakers.
Republican Senator Kelly Ayotte said the number remaining was a "joke".
"We have to acknowledge this is a total failure. I wish it weren't so, but that's the fact," said another Republican Senator, Jeff Sessions.
Gen Austin, who heads the US military's Central Command (Centcom) was appearing before the Senate Armed Services Committee.
Asked how many US trained rebels were fighting he said: "It's a small number... we're talking four or five."
He said there was clearly no way of meeting the goal of 5,000 recruits a year, but urged patience.
"It is taking a bit longer to get things done, but it must be this way if we are to achieve lasting and positive effects."
Appearing alongside him, Christine Wormuth, Undersecretary of Defence for Policy, said around 100 more rebels were currently in training.
She said the reason for the low numbers was the vetting process used, with the US only recruiting rebels wanting to fight IS rather than Syrian government forces.
It is not clear what happened to all of the initial group attacked in northern Syria - some were killed, others captured, while the rest scattered.
Gen Austin also promised "appropriate actions" if an investigation found than senior defence officials doctored intelligence to downplay IS and al-Qaeda strength in Syria.
The allegations that intelligence analysts' reports were being manipulated first emerged in the Daily Beast earlier this month.