The diplomatic battle between the U.S. and Russia over Syria escalated Wednesday, with Secretary of State Hillary Rodham Clinton calling on Russia to stop arming the embattled regime and Moscow charging the U.S. of providing weapons to the Syrian opposition.
Foreign Minister Sergei Lavrov acknowledged in Moscow that Russia is supplying "anti-air defense systems" to Damascus, a deal he said "in no way violates international law.
"[This] contrasts with what the United States is doing ... which is providing arms to the Syrian opposition that are being used against the Syrian government."
Warning that the situation in Syria is "spiraling towards civil war," Mrs. Clinton, as well as the White House, flatly rejected Mr. Lavrov's accusation that the U.S. is arming Syrian rebels.
"The United States has provided no military support to the Syrian opposition. None," Mrs. Clinton said.
"We do not and have not supplied weapons to the Syrian opposition," White House spokesman Jay Carney told reporters Wednesday. "You know our position on that, and we've made it very clear. That position has not changed."
U.S. assistance to the Syrian rebels has been non-lethal in nature, Mr. Carney said, consisting of sanctions aimed at pressuring Mr. Assad, as well as humanitarian aid to the Syrian people.
Just a day earlier, the secretary said she was concerned about reports Russia is providing attack helicopters to the Syrian government, a longtime ally, a charge Russia denies. On Wednesday she said the U.S. has "repeatedly urged the Russian government to cut these military ties completely and to suspend all further support and deliveries."
The finger-pointing between the two superpowers over Mr. Assad's bloody crackdown on opponents to his regime comes just days before President Obama and recently elected Russian President Vladimir Putin will meet for the first time at the G-20 summit in Los Cabos, Mexico, early next week.
The Russians' decision to provide weapons to the regime's military is not new, Mr. Carney said, but it remains a top concern for the U.S. and its allies who would like to see Mr. Assad overthrown and a smooth transition to a democratic form of government.
"We are engaged with the Russians on this issue as you know, and we obviously have some differences with the Russians on this issue," Mr. Carney acknowledged. "Where we broadly agree, I think, and where the entire international community agrees, is that we need to create a situation that allows for a transition in Syria during what remains a window of opportunity here, but a closing window of opportunity, to achieve that transition before the situation devolves into a broader sectarian civil war."
Russia has resisted Western efforts to pressure Mr. Assad to stop killing Syrian rebels and step down from power, joining China in vetoing a U.N. Security Council resolution calling for the Syrian president to step down earlier this year. Moscow and Beijing have both said they will never permit U.N. authorization of military force against Syria.
Despite its vetoes at the United Nations, Moscow has generally support the peace plan crafted by international envoy Kofi Annan. But that cease-fire plan has so far failed to prevent a series of deadly attacks by government forces on Syrian rebels.