[lloyd austin]Pablo Martinez Monsivais/AP Photo A top U.S. general has asked for permission to resurrect an effort to train Syrian opposition fighters for battles against Islamic State militants, but on a smaller scale than a previous program that failed and was scrapped last year. General Lloyd Austin, the head of Central Command, which oversees U.S. forces in the Middle East, told a Senate hearing on Tuesday that unlike the previous effort, which sought to recruit and train entire units of fighters outside the country to redeploy into Syria, the new program would focus on shorter-term training of smaller groups. "As we reintroduce those people back into the fight, they will be able to enable the larger groups that they’re a part of," Austin said. The failure of the original program, which sought to train thousands of fighters, was an embarrassment for President Barack Obama, whose strategy depends on local partners combating Islamic State militants in both Syria and Iraq. But the program was troubled from the start, with some of the first class of Syrian fighters coming under attack from al Qaeda's Syria wing, Nusra Front, in their battlefield debut. At one point, a group of U.S.-trained rebels even handed over ammunition and equipment to Nusra Front. "I've asked for permission to restart the effort using a different approach," Austin said. The U.S. strategy against Islamic State in Iraq and Syria, the home of the Sunni militant group's self-declared caliphate, aims to eventually force the collapse of its two major power centers of Mosul in Iraq and Raqqa in Syria. Austin told the Senate hearing that he made recommendations, now being reviewed at the Pentagon, about the types of additional U.S. capabilities that would be needed to accelerate operations "as we look towards Raqqa and Mosul." Although he did not explicitly say he asked for more U.S. troops, Austin acknowledged that would allow him to obtain better intelligence, offer greater assistance to local forces and to "increase some elements of the special operations footprint." [nusra front]Pablo Martinez Monsivais/AP Photo The United States has deployed a small number of special operations forces to Iraq with a mission to carry out raids against Islamic State there and in Syria. In Syria, dozens of U.S. special operations forces are helping enable forces on the ground with the Syrian Democratic Forces. U.S. General Joseph Votel, the commander of U.S. Special Operations Command, estimated that group was about 80 percent Kurdish. That could limit their ability to capture and hold predominantly Arab or other non-Kurdish communities in Syria. The timing of both the Mosul and Raqqa operations are also unclear. Mosul may not be recaptured this year, officials say. Votel acknowledged at the hearing that while the United States had a plan for local forces to isolate Raqqa, allowing it to choke off Islamic State's de facto capital, there was no plan yet in place to capture or hold the city. "I would say there’s not a plan to hold Raqqa," Votel said. _(Reporting by Phil Stewart; Editing by Chizu Nomiyama and Grant McCool)_ NOW WATCH: IAN BREMMER: Greece is headed for a humanitarian disaster