Russian 'reset' faces test as meetings loom on Iran, Syria

President Obama's Russian "reset" will face another big test Monday, as he and his diplomats meet with their Moscow counterparts in two different cities on two of the trickiest foreign policy challenges of his administration -- Syria and Iran.

In the Mexican city of Los Cabos, Obama is expected to meet with Russian President Vladimir Putin on the sidelines of the G-20 summit and have the chance to press Putin over the worsening situation in Syria.

In Moscow the same day, negotiators from the U.S. will join diplomats from Russia and other countries to meet with Iran over its nuclear program.

Efforts to stanch the violence in Syria and check Iran's nuclear program have hit serious roadblocks in recent weeks, and Russia is considered critical to untangling both messes.

Yet the minimal progress has drawn renewed criticism of U.S. policy toward Moscow, albeit criticism that falls on the upswing of the presidential campaign season.

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    As Secretary of State Hillary Clinton exchanged accusations this past week with Russia over its alleged support for Syrian leader Bashar Assad, Obama's Republican opponent Mitt Romney released a terse statement declaring that the U.S. approach to Russian relations had "clearly failed."

    Romney cited Russia's support for Assad as well as its alleged protection of Iran from international sanctions.

    Russia, though, is still seen by some as key to resolving these standoffs. Russia has gone along with U.N. Security Council efforts to tighten some penalties against Iran over its nuclear program, though it has blocked the harshest punishments.

    The U.S. remains under pressure to tighten the screws on Iran this week, with or without robust Russian backing.

    Dozens of U.S. senators from both sides of the aisle penned a letter to the president Friday urging Obama to stand tough against Iran in the upcoming talks. With new sanctions expected to take effect at the end of June, the lawmakers pressed the president to hold to them unless Iran truly reverses its position on nuclear program transparency.

    The senators backed the proposal floated at the last round of talks in Baghdad to compel Iran to halt uranium enrichment above 5 percent and export all uranium currently enriched above that level.

    Iran, though, bristled at that proposal in May.

    Dan Gillerman, former Israeli ambassador to the United Nations, said the U.S. needs to do more to convince the Iranians that military action is a real possibility.

    "The Iranians are using those talks to lull the world, put it to sleep and play the clock," he said Sunday on Fox News.

    Meanwhile, Obama faces an equally challenging task in trying to bring Russia back around on Syria.

    Diplomatic hopes have rested on Washington and Moscow agreeing on a transition plan that would end the four-decade Assad family rule. Russia, as Syria's longtime ally and trading partner, is seen as the best broker for a deal that could give Assad political refuge.

    So far, Moscow has said no.

    There is no formal meeting on Syria scheduled at the G-20, but U.S. and other diplomats have said they expect Syria to be a main topic in other settings.

    The White House tried to soften the blow of Clinton's accusation days before the G-20 meeting that Russia was equipping the Syrian government with attack helicopters that could be used against civilians. She later acknowledged they were only helicopters already owned by Syria that had been sent back to Russia for repairs, but Russia was already annoyed.

    Russia insists that any arms it supplies to Syria are not being used to quell anti-government dissent that began more than a year ago, and has rebuffed efforts to impose an international arms embargo. Russia and Syria have a longstanding military relationship and Syria hosts Russia's only naval base on the Mediterranean Sea.

    The United States has refused to arm anti-Assad rebels, in part to avoid a proxy fight in which Iran and Russia and others arm one side and the U.S. and Sunni Arab states arm the other.

    Opposition groups estimate 13,000 people have died in violence that the U.S. fears is sliding into civil war.

    The administration continues to defend its policy toward Russia.

    "The reset with Russia was based on the belief that we could cooperate with them on areas of common interest, understanding that we saw some differences," White House Deputy National Security Adviser Ben Rhodes said Friday.

    Things got off to a rocky start this spring, when Obama pointedly withheld a customary congratulatory phone call to Putin until days after his election. Putin appeared to snub Obama by skipping the smaller and weightier Group of Eight meeting that Obama hosted last month at Camp David.

    The Associated Press contributed to this report.