WASHINGTON: Tensions between the United States and Russia have sharply escalated since a massacre in Syria, as Moscow holds firm in the face of US charges that it has emboldened Bashar al-Assad's regime.
The latest friction comes weeks into a new term by Russian President Vladimir Putin, who has little patience for Western criticism and has already butted heads in a longstanding row over a NATO missile shield in Europe.
Russia and Iran are Syria's primary allies and the United States has ramped up criticism since the May 25 massacre in pro-opposition Houla, where gunmen rounded up and killed 108 people, 49 of them children.
Secretary of State Hillary Clinton, on a tour of Scandinavia and Russia's Caucasus neighbors, has denounced Moscow's arms sales to Syria and warned that Moscow's policies could help spark a "civil war."
Russia hit back, pinning blame for the massacre on foreign support for the rebels. Syria is Moscow's main remaining foothold in the Arab world and provides access to the Mediterranean Sea at the port of Tartus.
Putin has vowed not to repeat the experience of Libya, where a NATO campaign helped topple strongman Moamer Kadhafi after Russia and China abstained from a UN Security Council vote. Putin has held firm on arms sales, denying that Russia has supplied any "weapons that could be used in a civil conflict."
Russia expert Matthew Rojansky said that Moscow wanted to demonstrate that -- like virtually no other country, with the possible exception of China -- it had the power to act as it chooses.
"It's not just a matter of principle, but it's almost a litmus test for the independence and the freedom of Russia's hand globally," said Rojansky, deputy director of the Russia and Eurasia program at the Carnegie Endowment for International Peace.
"Can Russia act, even against the clear sentiments of the United States -- the putative global leader -- and the collective West? This is Russia's proof, yes we can."
Experts said that Russia also had clear policy differences with the United States over Syria as Moscow worried that Western powers were overlooking the possibility of Islamic hardliners replacing the secular-minded Assad.
President Barack Obama's administration rejects accusations that Al-Qaeda has infiltrated the Syrian opposition. Syrian dissidents say that civilians account for most of the 13,000 people killed since an uprising broke out in March 2011 against the Assad family's four-decade reign.
Obama has demanded that Assad step down and offered logistical support to the opposition. But his administration -- which is seeking to wind down a decade of war in Afghanistan after ending the controversial Iraq mission -- has ruled out the use of force in Syria.
To some observers, Russia provides a convenient rhetorical target in the absence of other options on Syria -- and Moscow sees the bluff.
"For the US, it's useful to point to Russia as obstructing action in the Security Council," said Mark Katz, a professor of government and politics at George Mason University.
"When the US is serious, the US doesn't bother to wait for Security Council approval -- we say that the Security Council can either join us or not. I think the Russians understand that we're not at that point and that the Obama administration is probably not going to get to that point either."
The Obama administration put an early focus on building cooperation with Russia in a policy dubbed a "reset" after some of the tensest times since the Soviet Union under former president George W. Bush.
But Russia voiced outrage after NATO activated on May 20 the first stage of a defense shield, which the Western alliance says is aimed at knocking out missiles from states such as Iran but Moscow sees as aimed at neutralizing its arsenal.
"When you deal with the Russians, it's important to recognize that everything is linked. If they're unhappy with the state of negotiations on missile defense, they're going to drag their feet everywhere else," Rojansky said.
Casting a shadow is the US election on November 6. Obama's Republican challenger, Mitt Romney, has attacked the president as too conciliatory and branded Russia as the top US foe.
In March, Obama was caught on an open microphone telling Putin's predecessor Dmitry Medvedev that he would have more "flexibility" after the election.
"Nobody expects the relationship to get much done between now and November," Rojansky said. (AFP)