Fighters from an alliance of insurgents known as the "Army of Fatah" (Islamic Conquest) work on a tank that belonged to forces loyal to Syria's President Bashar al-Assad in Hama province, Syria, on Aug. 10. (Ammar Abdullah/Reuters)

It was a dismal debut for an initiative already beset with problems: Shortly after their arrival at an outpost in northern Syria, dozens of U.S.-trained fighters were hit by a surprise assault by 50 al-Qaeda militants. A few days later, five of them were abducted by Islamists. Within weeks of the start of their mission, the new force had disbanded.

Now, U.S. military officials are reexamining how they will utilize the members of what the Pentagon is calling the New Syrian Force, given that the scale of the U.S-backed fighting force is dramatically smaller than expected, and it has already proved vulnerable to a multitude of adversaries within Syria. Officials acknowledge that they don’t have answers.

“Look, conditions have changed and now those conditions warrant a look at how we best employ them,” a U.S. military official said, referring to members of the Syrian force. “A lot of questions are being asked.”

Although no formal review is underway, officials said the special operations unit of U.S. Central Command, which oversees the training program, is leading the effort to reassess aspects of the program in the wake of battlefield and training setbacks.

“Clearly this first cohort and how they were reinserted into Syria caused us to learn some lessons. And clearly we are going to apply these lessons in the future,” said a U.S. defense official who, like others, spoke on the condition of anonymity to discuss internal deliberations. “How so, we don’t know yet.”

Officials stress that they are not considering terminating the program or altering its overall goal — the creation of a force of moderate Syrian rebels who could contain the Islamic State.

But officials are reassessing important aspects of the program, including how many troops can be trained each year, now that the goal of up to 5,400 trainees a year appears wildly optimistic. The White House introduced the program last year as officials scrambled to respond to the Islamic State’s expansion across Syria and Iraq.

After repeated delays, trainers from the U.S. Army’s 5th Special Operations Group began training Syrian cadets in May. For months, officials had struggled to find suitable candidates for the program — men who were old enough, healthy enough and, crucially, willing to pledge allegiance to a force that would be fighting the Islamic State rather than troops loyal to Syrian President Bashar al-Assad.

In July, a first class concluded its preparations and was sent into Syria. A second class, which officials say is not much bigger than the first cohort of 54, is now being trained.

More important, officials also are reexamining whether the force’s mission should be modified to compensate for its small size, the risks of which were laid bare during an attack on July 29 near the Syrian town of Azaz. The Syrians were able to repel the attack by fighters from Jabhat al-Nusra, Syria’s al-Qaeda affiliate, with the help of U.S. air support.

Currently, the fighters are tasked with securing areas of northwest Syria from Islamic State fighters. But a small unit could be inserted into a larger grouping, such as the Division 30, the larger unit from which they were drawn, to better protect them. They also could be given a more narrow set of responsibilities, perhaps calling in airstrikes or simply providing American military increased visibility of the situation on the ground.

U.S. officials said it is too soon to say what changes may be made to the way the troops are deployed. Neither do military officials know exactly how the force will fit in with a new “safe zone” that recently received the joint blessing of Ankara and Washington.

Privately, military officials express frustration with the perception that a training program just getting off the ground has foundered, while a covert CIA program to train Syrians has faced much less public scrutiny.

The program is regarded with ambivalence in the U.S. military, where some officials have been skeptical from the start that a modest-sized force can make much difference at this stage of Syria’s multi-sided civil war. Presentation of the training plan last year brought a hasty conclusion to a long internal debate about whether the United States should train and equip forces in Syria, fueling a perception that the White House was searching for a way — any way — to demonstrate its resolve in Syria.

Congressional officials say the program must achieve momentum before the end of the year or the administration may jeopardize funding and support for the training in next year’s annual defense legislation. The Pentagon has spent more than $41 million on the program.

Military officials say it’s too soon to write off the New Syrian Force’s first class, let alone the larger program. They note that the force is just one component of a bigger U.S. effort to cultivate and support ground forces, including government and tribal forces in Iraq and Kurdish fighters in Syria, against the Islamic State.