Bradford Plumer over at New Republic's blog The Plank writes:

So the New York Times reports today: "Russia has informed Iran that it will withhold nuclear fuel for Iran's nearly completed Bushehr power plant unless Iran suspends its uranium enrichment as demanded by the United Nations Security Council." Smackdown! Or maybe not. According to Bloomberg, Russia is now denying that it ever issued such an ultimatum, and is really only withholding the fuel because of a dispute over late payments (which would make perfect sense). If anyone wants to parse all the various statements here, feel free. This bit from the Times piece, though, was intriguing:

The Russian Atomic Energy Agency, or Rosatom, is eager to become a major player in the global nuclear energy market. As Security Council action against Iran has gained momentum and Iran's isolation increases, involvement with the Bushehr project may detract from Rosatom's reputation.

That seems like as plausible a reason as any for Russia to decide to confront Iran over the latter's enrichment program. Although if the denials to Bloomberg are true, it hasn't really reached that point yet.

In a post entitled "Russia Plays a Murderous Game," Scrutiny Hooligans adds:

Russia, after years of arming Iran with conventional weaponry and nuclear technology, is now playing Mr. Nice Guy with the world community by threatening to withhold the nuclear material for Iranian power plants. Well so what, right? Just as long as Iran doesn't go nuclear, we can avoid war, right? You wouldn't think so if you look at the way the Russians are peddling arms to our rivals,

"Last year, Russia surpassed the United States as the developing world’s leader in arms deals, according to a new report by the Congressional Research Service (CRS). But Russia has increased military shipments to anti-U.S. states like Iran and Venezuela, not to mention potential adversaries like China, which concerns U.S. policymakers far more. Experts say Iran—as well as Syria—may have transferred some of these small arms to groups like Hezbollah and Hamas."

Russian behavior indicates that we've made things rather hot in Vladimir Putin's kitchen right about now. We need to keep up the pressure until Russia is forced to abandone its crazed machinations in Iran; it's the perfect (and essential) test case to demonstate Western resolve.