The outcome of that effort could have immense ramifications for the Middle East and particularly for U.S. President Barack Obama's outreach to Tehran to engage in diplomatic dialogue to resolve the question of Iran's controversial nuclear program and relations with "the Great Satan."
Israel's Haaretz daily reported June 29 that Prime Minister Binyamin Netanyahu telephoned his Russian counterpart, Vladimir Putin, and urged him to ensure that none of the S-300PMU missiles Tehran has reportedly bought from Russia will be delivered.
Moscow has repeatedly claimed it has not delivered any of the five S-300 units it agreed to sell Iran under an $800 million contract it is said to have signed in early 2008.
But Haaretz reported that when Israeli Foreign Minister Avigdor Lieberman visited Moscow several weeks ago, Russian President Dmitry Medvedev told him Tehran had made some payments for the missiles.
That added a critical new wrinkle to the problem at a time when the Iranian regime is busy crushing internal opposition triggered by the disputed re-election of firebrand President Mahmoud Ahmadinejad.
The Israelis' new push to stop Iran getting its hands on the S-300, considered one of the most effective all-altitude air-defense systems in the world, followed what one official in Tel Aviv described as a "noticeable change in Russia's position on the matter of the arms sale."
Haaretz said the deterioration in relations was detected during Lieberman's visit. Medvedev told him about the Iranian payments and said: "It's a lot of money. There's an economic crisis at this time and we're having a very difficult time."
Russia's RIA Novosti news agency provided some insight into the Russian position. "Arms deliveries to Iran are important to Russia because Moscow is quickly losing its position in key Asian arms markets in China and India," it reported.
Indeed, underlining Moscow's unease over its shrinking arms sales, Israel's mass-circulation Maariv daily reported that Medvedev had even suggested to Lieberman that Israel purchase the S-300s in question, or convince a third party to buy them, to keep them out of Iranian hands.
These developments came as Medvedev prepared to meet with U.S. President Barack Obama next week.
Obama is certain to support the Israeli position. He has pressured Israel not to launch any pre-emptive air or missile strikes against Iran to knock out critical parts of its nuclear program, which the Jewish state views as an existential threat.
For one thing, the Americans fear that if Russia does agree to deliver S-300s to Iran, the Israelis will take unilateral action.
Some U.S. officials are concerned that Israel, "for reasons of threat perception and, strategic planning culture and operational capabilities, would feel compelled to attack Iran's nuclear facilities before the SD-300s become operational," according to Jane's Intelligence Digest.
The Americans believe that the Israelis would have some success if they launched a pre-emptive strike, although it is highly unlikely that would knock out all of Iran's nuclear facilities.
But Washington is worried that whatever the outcome of an Israeli assault, they believe the United States would be blamed for condoning or supporting it.
"So U.S. diplomats are earnestly lobbying Russia not to complete the (S-300) sale," Jane's noted. "At the same time, U.S. defense experts are assessing how to enhance Israel's long-range strike capabilities to decrease Israel's perceived need to actually use them."
Meantime, just to add to the mushrooming problem, Russia's Interfax-AVN agency has reported that some African states, particularly Egypt, were interested in acquiring the S-300. Russian defense analysts said Egypt was a logical candidate since it already has extensive stocks of Russian air-defense missile systems.
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