Israeli officials downplayed reports in the Russian media Wednesday that Moscow signed a deal two years ago to sell S-300 air defense missiles to Iran, saying what is important is that the state-of-the-art weapons have not been delivered. Moreover, one diplomatic source said, Russian Foreign Minister Sergei Lavrov said "in the clearest manner possible" on a recent visit to Israel that Russia would take Israel's sensitivities on the matter into account. The Russian news agency RIA Novosti quoted on Wednesday a source at Russia's Federal Military Technical Cooperation Service as saying that Iran had not yet received any S-300 air defense systems under a 2007 contract, and that deal depended on the leadership in Moscow. "Russia is interested in fulfilling the contract, which is worth hundreds of millions of dollars," the source said, adding that it was a political decision that would largely depend on the international situation. He said, "the contract itself, though, is being gradually executed." Israeli diplomatic sources said that there was nothing really new in the Russian media reports about the sale. Russia's Kommersant newspaper had already reported in February that Russia and Iran had signed an $800 million deal for five of the S-300 systems, but Moscow had not yet decided whether to ratify the sale. But some Israeli experts say that the acknowledgment by a Russian official of the existence of an S-300 contract with Teheran could be a Russian signal to Washington signifying Moscow's readiness to abandon the deal. Emily Landau, director of the Arms Control and Regional Security Program at Tel Aviv University's Institute for National Security Studies (INSS), said the statement could be placed in the context of a wider US attempt to thaw relations with the Russians. Washington has reportedly made informal proposals to abandon its missile defense systems, slated to be installed in countries neighboring Russia, to Moscow's ire, in exchange for cooperation from Moscow against Iran. Russian President Dmitry Medvedev is scheduled to meet US President Barack Obama next month to discuss nuclear disarmament issues and the deployment of US missiles in Eastern Europe. "Generally speaking, US President Barack Obama seems to have offered the idea of a kind of trade-off to the Russians. It was reported that Obama suggested that if Iran was no longer a concern, then missile defense directed at the Iranian threat would not longer be so important," Landau said, adding that both sides have officially denied discussing such a deal. "I think that within this discussion and possible trade-off, the issue of the S-300 comes into the picture. What was said by the Russian official could be a confirmation of a positive signal to the US, saying, yes, we did sign a contract, but we are freezing the deal," Landau added. "There seems to be more evidence that this is a way for Russia to tell the US, 'we did make a commitment, but we are willing to go back on that commitment in the context of discussions,'" she said. "It's clear that the Russians are playing with the issue of the S-300. There had been other statements from Russia earlier in March indicating that this had become a political issue," Landau said. "I think this could be positive." Ephraim Kam, deputy head of the INSS and a specialist in security intelligence described the S-300 air-defense system as being "one of the best in the world," adding that Iran had been trying to acquire it for nine years to protect its nuclear facilities. Last month Iranian Defense Minister Mostafa Mohammad Najjar visited Moscow, apparently to lobby for the deal. But at the same time that Najjar was in Moscow, Lavrov was in Israel and government officials said that Jerusalem heard "very clearly" from Lavrov that Russia would not sell weapons to any countries in the area that would tip the strategic balance in the region. The S-300 is considered to be just such a weapon. It is one of the most advanced multi-target anti-aircraft missile systems in the world, with a reported ability to track up to 100 targets simultaneously while engaging up to 12. It has a range of about 200 km. and can hit targets at altitudes of 27,000 meters. Iranian possession of the system would significantly complicate an Israeli or US strike on Iranian nuclear installations.