Citing US and Syrian sources, the US daily wrote that the CIA had begun delivering shipments of lethal aid in the past fortnight.

The newspaper reported on its website that the US State Department has sent separate shipments of vehicles and other materials, including new types of non-lethal gear, sophisticated communications equipment and advanced combat medical kits.

The CIA said it had no comment on the Washington Post report.

The arms shipments -- which the daily said are limited to light weapons and other munitions that can be tracked -- arrive at a crucial moment in the bloody standoff between the rebels and the Damascus government.

The Post cited US officials who said the goal of the non-lethal assistance is to help foster cohesion among units of Syria's disjointed armed opposition.

US President Barack Obama Tuesday agreed to give international diplomacy a chance to resolve the conflict before unleashing military strikes.

The long-awaited military aid comes one day after the US president told the American people in a nationally broadcast address that he was deferring taking military action in Syria in order to study a Russian initiative which would see Damascus relinquish its chemical weapons.

He made his appeal to US lawmakers after a weeks long build up to war in which he sought congressional approval for military strikes against Syria for using chemical weapons on its own people.

Obama made his threats of strikes in response to the August 21 attack, when Syrian forces allegedly killed 1,400 people in rebel-held areas near Damascus using sarin gas, according to US estimates.

But the US leader in his speech late Tuesday gave assurances that there would be no military force for the moment, given the Russian plan.

"This initiative has the potential to remove the threat of chemical weapons without the use of force, particularly because Russia is one of Assad's strongest allies."