Washington: Rebels fighting to depose Syrian president Bashar Al Assad have for the first time acquired a small supply of surface-to-air missiles, according to a news report that a Western official did not dispute.

NBC News reported on Tuesday night that the rebel Free Syrian Army had obtained nearly two dozen of the weapons, which were delivered to them via neighbouring Turkey, whose government has been demanding Al Assad’s departure.

Indications are that the US government, which has said it opposes arming the rebels, is not responsible for the delivery of the missiles.

But some US government sources have been saying for weeks that Arab governments seeking to oust Al Assad have been pressing for such missiles, also known as MANPADs, for man-portable air-defence systems, to be supplied to the rebels.

In recent days, air operations against the rebels by Syrian government forces appear to have been stepped up, particularly around Aleppo, making the rebels’ need for MANPADs more urgent.

Precisely what kind of MANPADs have been delivered to Syrian rebels is unclear and NBC News did not provide details. Such weapons range from the primitive to highly sophisticated.

And even if the rebels do have the weapons, it is unclear whether they have the training to operate them effectively against Al Assad’s air forces in the immediate future.

Some conservative US lawmakers, such as Republican Senators John McCain and Lindsey Graham, have criticised the administration of President Barack Obama for moving too slowly to assist the rebels and have suggested the US government become directly involved in arming Al Assad’s opponents.

The White House, at least until now, has taken a considerably more cautious approach.

As of last month, US officials warned that if any Middle Eastern nation was “even considering giving arms to the Syrian opposition,” it ought to “take a measured approach and think twice about providing arms that could have unintended consequences.”