Fresh back from a five-day trip to China, Prime Minister Binyamin Netanyahu is expected to make a lightning visit to Russia this week, government officials confirmed Saturday night, amid concerns Russia may deliver advanced air defense missiles to Syria.Netanyahu is expected to meet Russian President Vladimir Putin at his residence at Sochi, on the Black Sea Coast.The Wall Street Journal reported on Wednesday that Israel had informed the United States that a Russian deal was imminent to sell S-300 advanced ground-to-air missiles to Syria. The threat of such a sale is believed by some to be a Russian effort to deter the West from either intervening in the Syrian civil war or to sell arms to the Syrian rebels.Russia is Syrian President Bashar Assad’s main international backer, outside of Iran.The Russian news agency RIA Novostoi reported that Russian Foreign Minister Sergei Lavrov said Russia had no plans to supply Syria with weapons beyond current contracts that Moscow is honoring.According to the Wall Street Journal, Israel told the US that Syria was making payments on a 2010 agreement with Moscow to buy four batteries for $900 million. The report said the package included six launchers and 144 operational missiles, each with a range of 200 kilometers, with an initial shipment expected in the next three months.Over the last decade Israel has urged the Russians on numerous occasions not to sell “game-changing” weapons systems either to Iran or Syria.Some five years ago, during a visit to Russia by then prime minister Ehud Olmert, Moscow pledged not to sell weapons in the region that would “tip the strategic balance.” And, indeed, in 2010 the Russians backed away from delivering S-300 missile batteries to Iran, despite a contract the two countries signed in 2007.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. 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 – including incoming missiles – at altitudes of 27,000 meters.Netanyahu has not been to Russia since 2010, though Putin visited here in June 2012, shortly after being elected president again a month earlier. Putin invited Netanyahu to visit Russia in a letter of congratulations sent to Netanyahu for forming a new government and delivered just hours before US President Barack Obama arrived in Jerusalem in March.On Thursday, US Secretary of State John Kerry said Washington did not want Russia to sell weapons to Syria and has opposed transfers of missile systems to the country in the past because of the threat to Israel.“I think we have made it crystal clear we would prefer that Russia was not supplying assistance,” Kerry said at a news conference after meeting Italian Foreign Minister Emma Bonino.Pressed about the report about an imminent sale of the S-300s, Kerry suggested he may have raised the issue with Putin and Lavrov, whom he met in Moscow on Tuesday. After those meetings, the two countries agreed to seek new peace talks to end the Syrian civil war.“I had my say with President Putin and I had my say with Sergey Lavrov and we made an agreement to go to a negotiation in the next days and I am not going to get into here, now, at this moment, as I said, distinguishing features between one country’s aid and another country’s aid and who’s doing what,” Kerry said.“That would be counterproductive to what we are trying to accomplish,” he added.Reuters and Jerusalem Post staff contributed to this report.No exact date for the meeting has yet been given. Netanyahu spoke with Putin from China last Monday.