(JNS.org) Russia has started the delivery of the advanced S-300 air defense system to Iran, despite American and Israeli objections. The S-300 surface-to-air-missile was initially developed under the Soviet Union, and its newer variants are regarded as the most potent anti-aircraft missile systems in the world. Initially signed in 2007, the $800 million deal between Iran and Russia for the S-300 system was suspended in 2010. But in April, Russian President Vladimir Putin lifted the suspension after the framework nuclear deal between Iran and the P5+1 powers. A Russian official in early November, several months after the final nuclear deal was reached, confirmed that the sale was moving forward. The U.S., Israel, and Saudi Arabia have all opposed the sale of the S-300 system to Iran. Israel and the U.S. fear that the missile defense system could make it more difficult to use the military option against Iran’s nuclear program.