The United States has stopped pulling new recruits from the battlefield in Syria for training outside the country while the U.S. military program to forge a force of moderate rebels undergoes review, a Pentagon spokesman said on Tuesday.

Despite the problems, the Pentagon said the program was still active, with recruiting and training ongoing. "As we review the program, we have paused the actual movement of new recruits from Syria," said Peter Cook, a spokesman for the Pentagon in Washington. "We also continue to provide support for current forces on the ground and to train the cohorts currently in the program."

The program now consists of a handful of trained fighters left on the ground to fight the Islamic State of Iraq and al-Sham (ISIS).

Some 75 U.S.-trained fighters entered Syria last week and took up positions on frontlines against ISIS in Aleppo, according to the Syrian Observatory for Human Rights. Allegedly, however, fighters handed over some of their equipment to the Nusra Front last week in return for safe passage, in violation of program guidelines.

They were the second group of fighters that were part of the plan, while the first group, Division 30, was overwhelmingly defeated in a pitched battle with the Nusra Front in July. More than half of the soldiers of Division 30, including the commanding officer, were taken captive or killed, and the whereabouts of 18 other fighters are unknown, a U.S. military spokesman said this month. Questions increased about the future of the program following the development.

On Sept. 16, Gen. Lloyd Austin, commander of U.S. Central Command (CENTCOM), admitted before a U.S. Senate hearing that the train-and-equip program has been a total failure – at the cost the $500 million to taxpayers. Moreover, out of the 54 trained fighters sent to fight ISIS, Austin said only a few remain. "It's a small number. We're talking four or five," he said.

According to the plan, groups of 300 to 2,000 Free Syrian Army (FSA) soldiers were to be trained. However, Pentagon officials reported in August that the program is moving slower than expected due to complications in vetting volunteers and transporting them from Syria for training.

Turkish media outlets reported that dozens of fighters withdrew from the program after they refused to sign a contract assuring that they would not fight against the Syrian regime. Many Syrian volunteers prefer to use their training to fight both ISIS and forces loyal to Syrian President Bashar Assad, which was the original aim of the revolution before it became more complicated.