President Vladmir Putin reportedly froze the transfer of the S-300 anti-aircraft missile system to Iran after receiving evidence that Tehran had transferred advanced weapons to Hezbollah.
After Russian President Vladimir Putin receiving intelligence proving that weapons Russia sold to Iran were ending up in the hands of terrorists, Putin has frozen the transfer of S-300 surface-to-air missile systems to Tehran, reported Arab news sources on Saturday.

Source: News Agencies, 7 March 2016