The United States is stepping up support for the Syrian rebels but, despite the failure of UN envoy Kofi Annan's mission, is sticking to its refusal to pour arms into a complex conflict.
Annan, the UN and the Arab League's pointman on Syria, resigned on Thursday, leaving the diplomatic track in shreds and spurring calls for action, but the US administration again said it was not considering military intervention.
"Our position has not changed: We provide non-lethal assistance to the opposition," White House spokesman Jay Carney said aboard Air Force One.
"We don't believe that adding to the number of weapons in Syria is what's needed to help bring about a peaceful transition."
The 17-month uprising against Assad has already cost more than 20,000 lives, many of them civilian, and raised fears that the embattled Syrian leader could unleash his arsenal of chemical weapons.
Some experts and US lawmakers now openly question whether Washington should not use its superior military strength and intelligence capabilities to tip the scales in the favor of the opposition and hasten the regime's demise.
But the US administration is reluctant to become embroiled in a another Middle Eastern war with November's election looming.
Fearing a post-Assad bloodbath in Syria, it has insisted that adding more weapons into the mix -- beyond Assad's impressive government stockpile and the rebels' growing arsenal of smuggled guns -- would only fuel more violence.
"Our analysis is that the regime's capability is being weakened. That the Syrian army soldiers are becoming demoralized and that the Syrian opposition are gaining ground," a State Department spokesman, Patrick Ventrell, said.
"So our strategy is having an effect," he insisted. "We are going to continue to use every lever that we have in our plan to hasten the day that Assad steps aside."
Reports on Wednesday citing unnamed US officials said President Barack Obama had signed a document allowing covert support to the rebels and which would authorize clandestine action by the Central Intelligence Agency.
That would permit Washington to offer all kinds of assistance, including organizing contact with various rebel groups, providing communications and intelligence assets and assessments.
And, while Washington may not be directly providing arms, some of its allies are, as part of a regional strategy prioritize direct involvement by Syria's neighbors with Washington's support and ultimately weaken US foe Iran.
"The fact of the matter is that the rebels are getting the support, there is a strategy in place to have the regime fall, a crack from within," Reva Bhalla of Stratfor, a global intelligence forecasting consultancy, told AFP.
"The US is not hiding the fact that it is very involved there and using those covert channels as Turkey and the Saudis are," he said, pointing to the fact that the rebels now appeared to be fighting with heavy weapons.
"Let's be realistic here -- those weapons are getting to the rebels, even if it is not coming from the US directly, the rebels do seem to be getting that kind of support."
Some $25 million in non-lethal US support such as communications has already been earmarked for the Syrian opposition.
And on Thursday, Obama approved an extra $12 million in humanitarian aid for Syrians to mitigate what he said were Assad's "horrific atrocities."
The grant brings to $76 million the amount of food, water, medical supplies and other aid being funnelled via agencies like the World Food Program and the UN High Commissioner for Refugees to some of the 1.5 million Syrians in need.
US strategy was "to accelerate our sanctions, to squeeze this regime as they run out of money, it's to assist the opposition so they can better communicate and organize and get around a political transition plan," Ventrell said.
Washington blamed Annan's departure on Russian and Chinese intransigence after both nations three times blocked resolutions in the United Nations Security Council to impose sanctions on the Assad government.
"I did not receive all the support that the cause deserved," Annan said, as he announced the end of his mission.
Ventrell said that "given where we are, given the continued onslaught and given where... there's not a Security Council consensus on this, it's not surprising that we are seeing him step down."
But the United States maintained that Annan's six-point plan was "a framework we continue to support and to go forward with in the context of our wider strategy."