CNN  — 

The Pentagon is poised to begin, as soon as this week, a controversial program to train moderate Syrian rebels at locations in Turkey and Jordan to fight ISIS, according to several U.S. defense officials.

The first of 400 U.S. military trainers have now arrived in both countries. Out of a list of 3,000 rebels who have expressed interest in joining the program, some 400 have passed the initial security screening. Once final approval is given, they will be training on small arms, radios, medical gear and battlefield tactics.

The plan is for them to return to their towns and villages and be able to specifically defend them against ISIS. However, U.S. officials are aware, they say, of the risk that some of the trained fighters could decide to take their weapons and fight the Assad regime which is not the goal of the training.

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The U.S. plans to provide them with weapons, trucks and tactical radios so they can communicate among themselves on the ground. No final decision has been made about any U.S. provided protection – such as airstrikes against ISIS or the Assad regime – for the rebels when they return home.

The Turkish government has already talked about the training efforts, but so far the US doesn’t expect Jordan will openly discuss the training due to regional sensitivities.

But a top opposition force leader in Syria told CNN’s Jim Sciutto on Wednesday in an exclusive interview that the U.S. support for the group fighting the embattled Assad regime is “too small and too slow.”

Khaled Khoja, president of Syrian National Coalition, said that out of the 70,000 strong Free Syrian Army force, he needs 30,000 to be trained, preferably by U.S. Troops. The U.S. and coalition train and equip program, which is about to begin, currently plans to train just 5,000 fighters a year.

“We have the capability and the ability to fight against the terrorism and against the terror led by the Syrian regime,” said Khoja. “But we need to include much more fighters from the FSA (Free Syrian Army) in this program and we need to have it much more faster.”

Khoja, who is ending an almost week-long trip to New York and Washington to discuss U.S. policy in Syria, expressed disappointment in Syria’s “American friends.”

He asked for sophisticated weapons, especially anti-aircraft weapons, to defend against Syrian air strikes and for U.S. help to protect safe havens, or “no-go zones” for Syrian rebels, but he said he’s leaving Washington with no promises.

“It’s very weak support,” Khoja said. “What we need is to have our own military equipment in order to defend the freed areas. Since we did not receive any kind of this sophisticated arms we cannot defend the people from the barrel bombs thrown by the Assad regime.”

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With a fluid situation on the ground, there is concern in the U.S. that heavier weapons could fall into the hands of terror groups like ISIS or al Qaeda affiliated al Nusra that are operating freely out of Syria. Khoja denied allegations that the Free Syrian Army and al Nusra are working together, though they appear to be working toward a common goal.

“There is no cooperation on the battlefield but sometimes when we are fighting Assad forces and fighting ISIL … it looks like cooperation between al Nusra and FSA groups,” said Khoja. “But we are firmly condemning al Nusra.”

Pointing to Saudi Arabia’s air campaign against the Iranian backed Houthi rebels in Yemen, Khoja says he expects greater support for their fight against the Syrian regime, which also is supported by Tehran, from Arab countries in the Gulf region.