Russia has frozen the sale of the state-of-the-art S-300 anti-aircraft missiles to Iran, the Russian newspaper Kommersant reported Wednesday. Iranian Defense Minister Mostafa Mohammad Najjar was reportedly informed of the decision by his Russian counterpart Anatoly Serdyukov on his visit to Moscow on Wednesday. Russia said the delivery of the systems would be delayed at least until the upcoming meeting between President Dmitry Medvedev and his US counterpart, Barack Obama. Kommersant cited Russia's wish to prevent hindering dialogue with the new US administration. Military diplomatic sources were quoted by Kommersant as saying that the issue had been the focus of Najjar's visit. Israel Radio quoted Moscow sources as saying that apart form the gesture to the Americans, Russia also wanted to avoid ruining a $100 million drone purchase from Israel. On Tuesday, Kommersant that Russia and Iran had already signed an $800 million deal for five of the S-300 systems, but Moscow had not yet decided whether to ratify the sale. The S-300 is one of the most advanced multi-target anti-aircraft missile systems in the world, and has a reported ability to track up to 100 targets simultaneously while engaging up to 12. If Iran were provided with the system, it would significantly complicate any Israeli or US strikes on Iranian nuclear installations. The S-300 system was first deployed by the USSR in 1979 and was designed to defend large industrial and administrative facilities and military bases, and to control airspace against enemy aircraft. It has a range of about 200 km. and can hit targets at altitudes of 27,000 meters. Iran already has Russian-made TOR-M1 surface-to-air missiles, but they have a shorter range than the S-300.