The Iranian defense minister criticized Russia on Thursday for banning all sales of S-300 anti-aircraft missile systems to Iran.Thursday's comments by Gen. Ahmad Vahidi come a day after Russian President Dmitry Medvedev issued a decree on the ban.RELATED:Barak heads to Russia in bid to halt Iran, Syria arms dealReport: Iran obtains 4 S-300 missilesRussia: Sanctions ban S-300 missilesRussia signed a 2007 contract to sell the sophisticated systems that could boost Iran's ability to defend against air strikes. Israel and the United States have objected to the deal, and no such missiles have been delivered yet.Vahidi told Iranian state TV that the Russians are obliged to implement the 2007 contract.On Wednesday, Russia's chief of the military's general staff said said that UN sanctions were the reason for the decision."A decision has been taken not to supply the S-300 to Iran, they undoubtedly fall under sanctions," the ITAR-TASS news agency quoted Chief of General Staff Nikolai Makarov as saying."There has been an instruction from the country's leadership to stop the deliveries, and we are obeying it," Makarov added, according to state-run RIA-Novosti news agency.Israel has also been concerned at the possibility that Russia may follow through with the delivery of the S-300 surface-to-air defense system to Iran. Russia had previously issued mixed messages regarding the future of the 2005 deal, first saying that the new round of sanctions on Iran passed at the United Nations in June would not impede the deal, and later saying that it would.Yaakov Katz contributed to this report.