And in Moscow, President Vladimir Putin's foreign affairs adviser said Russia not convinced with Washington's claim that Syrian regime had used chemical weapons against the opposition. Yuri Ushakov told reporters the information provided by U.S. officials to Russia "didn't look convincing."
The commander of the main Western-backed rebel group fighting in Syria said he hoped that U.S. weapons will be in the hands of rebels in the near future, noting it would boost the spirits of the fighters on the ground. "We hope to have the weapons and ammunition that we need in the near future," Gen. Salim Idris told Al-Arabiya TV.
"This will surely reflect positively on the rebels' morale, which is high despite attempts by the regime, Hezbollah and Iran to show that their morale after the fall of Qusair deteriorated," he said, referring to the town near the border with Lebanon.
Obama's opposition to sending American troops into Syria makes it less likely the U.S. will provide sophisticated arms or anti-aircraft weapons that would require large-scale training. Administration officials are also worried about high-powered weapons ending up in the hands of terrorist groups. Hezbollah fighters are among those backing Assad's armed forces, and al-Qaida-linked extremists back the rebellion.
The CIA and special operations trainers are already running some weapons training programs for the rebels and are expected to take charge of teaching the opposition how to use the weapons the U.S. has agreed to supply, another U.S. official said.
There is also some debate within the administration about who would provide the lethal aid and how it might be delivered, the U.S. officials said.
All the officials insisted on anonymity to discuss internal administration discussions.