"The US and Israel told the Russians that if they sell this system to Iran, they will make sure to defeat the system (if not done so already). That will compromise Russian`s main air-defence system." - Dan from Haifa That is a good fantasy Dan. Russia sold a S-300PMU1 system to the USA long ago. It has been extensively tested and simulators devised for Red Flag training exercises. US units practice against a variety of defensive systems and aircraft all the time Dan. The 119 Squadron (The Bat Squadron), equipped with F-16I from Ramon Air Base, participated in Red Flat 09-4 just last July. How could your imagined 'threat' be true Dan?
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: Russia to supply Iran with S-300 defense systems