ISTANBUL -- It was supposed to be a crucial instrument of the Obama administration's aims in Syria, an ostensibly moderate rebel fighting force that would keep the pressure on the authoritarian regime in Damascus without aiding the ruthless jihadist forces that have captured much of the country. But the soldiers of Harakat Hazzm -- the first Syrian rebel group to receive arms from the CIA -- disbanded this week.

As a result, much of northern Syria is in the hands of the extremists, and the United States is left with no palatable ally in the area in the midst of a regional conflict that continues to spiral out of control.

Hundreds of Harakat Hazzm's soldiers have joined jihadist forces like Jabhat al-Nusra, the al Qaeda offshoot in Syria, and the Islamic State group, also known as ISIS, several former fighters told the International Business Times. The so-called moderate rebels complain that they had no alternative to joining al-Nusra and ISIS because the U.S. failed to supply adequate resources.

“It is a setback for the covert program and it makes the train-and-equip program that much harder,” said Andrew Tabler, an expert on the Syrian civil war at the Washington Institute for Near East Policy, a think tank based in Washington D.C. “It’s bad news for the U.S. and it’s a sign you can fight terrorism in Syria but you aren’t going to get local allies unless you are willing to give them what they want.”

Harakat Hazzm was the first Syrian rebel faction to receive long-range wire-guided missiles (TOW) from the U.S. as it fought in the northern countryside outside Aleppo. At its height in 2013, the group mustered some 5,000 soldiers, according to a group leader who asked to remain anonymous for security reasons. But the rebels opted to disband after losing hundreds of men in back-to-back battles against al-Nusra last weekend.

The breakup of Harakat Hazzm effectively nullified the two-year-old American campaign to prop up the rebels in the northern part of the country, and it presented a cautionary tale as the U.S. seeks to recruit and support moderate fighters in the southern reaches.

The CIA-led program that delivered support to Harakat Hazzm began in the spring of 2013, as the U.S. selected groups of rebels fighting under the Free Syrian Army. That program allowed for the transfer of U.S.-made weapons to Turkey, and was partially funded by Saudi Arabia and other wealthy Sunni states.

The moderate rebels in Syria called on Washington to send heavier artillery for months even before ISIS gained ground last summer. That aid never made it to the battlefield. And when ISIS bulldozed the border between Iraq and Syria in June, the rebels in Aleppo had to fight on multiple fronts, against Assad, ISIS and al-Nusra, with dwindling resources.

Recipients of U.S. lethal aid told IBTimes in interviews that the U.S. set them up for failure.

“The U.S. support was not enough for the rebels in the North to be strong and defeat the Islamic groups,” said Oussama Abu Zayd, one of the main advisers and an active member of Harakat Hazzm, adding that many moderate rebels defected to extremist organizations because they had more money. “They have millions of dollars from donors.”

According to data obtained by IBTimes, the Hazzm movement received a total of about $6 million in 2014 from the U.S. government -- $500,000 a month for 5,000 soldiers. Abu Zayd said that only 40 percent of Hazzm’s budget consisted of weapons. And until October, he said, the group received 20 TOW missiles every month -- far too little to take on ISIS.

“How could we be strong with that kind of budget?” he said. “The support the U.S. gave in Kobani was really support. The coalition agreed to get help from the Kurdish military and they sent money and helped in airstrikes. That is the real support we needed.”

In December, Secretary of State John Kerry said that the U.S. was engaging in new efforts to save the Syrian moderate rebels in the north from total defeat, but rebels in the northern countryside of Aleppo, some of whom fought with Harakat Hazzm and others who were members of smaller moderate factions, said that help never showed up. Hazzm leaders said they stopped receiving U.S. support back in the fall when the group began to lose ground.

In November, al-Nusra, also known as the Nusra Front, pushed Harakat Hazzm out of Idlib province and took over the movement’s headquarters there, seizing weapons, including some of the U.S. TOW missiles. And in January, Hazzm lost control of one of the only two open border crossings between Turkey and Syria -- the Bab al-Hawa crossing in northwestern Syria, on the road to Aleppo. Rebel groups linked to extremist factions took over.

The Department of Defense is taking over the task of propping up the rebels in Syria. It will be in charge of arming Syrian rebels and will also train them at military bases in Jordan. On Jan. 15 the Pentagon confirmed that it would send 400 U.S. military trainers and hundreds of personnel to the Middle East to train Syrian rebels. The program, which calls for the training of 5,000 rebels, will focus on defeating President Bashar Assad’s forces near Damascus. It is still unclear which rebels will receive U.S. weapons and training.

But analysts say, if the U.S. is to defeat Assad and ISIS, it needs to come up with a new strategy in the north. Since the downfall of Harakat Hazzm, moderate rebels still left in northern Aleppo have formed a new group called the Levant Front. “It is gaining steam,” Tabler said. “It is the nature of the Syrian battlefield for these groups to coordinate with al-Nusra. They all recruit from the same places. But there should ultimately be a bit of a difference moving forward.”

Although some of the rebel groups within the Levant Front have ties to al Qaeda, analysts think the group might be the best ally for the U.S. in the north. Some Levant Front fighters still have their U.S. weapons and military gear.

“It is not enough just to fight ISIS with airstrikes,” Abu Zayd said. “We need to change the U.S. policy and support the Levant Front on the ground to have any real effect.”