Iran on 17 April 2016 unveiled S-300 missile system parts at army parade in Tehran. It was a long-awaited air defence system ordered from Russia.
The S-300 system was on order since 2007 but Russia postponed the sale three years later after the UN Security Council (UNSC) passed a resolution relating to Iran's nuclear programme.
A deal between Iran and six world powers over its nuclear activities which led to lifting of sanctions in January 2016 removed the barriers to delivery but the fully operational system is still awaited.
Iran insists the system is necessary to defend itself from threats of attack, including possible bombing of its nuclear facilities, and the S-300 would allow early detection of approaching aircraft.
Iran and Russia are also in talks on a sale of the Sukhoi SU-30 fighter, another proposal criticised by the US.
About S-300 Missile System
• The S-300 is a series of initially Soviet and later Russian long range surface-to-air missile systems produced by NPO Almaz, based on the initial S-300P version. It was first deployed by Russia in 1979.
• The S-300 system was developed to defend against aircraft and cruise missiles for the Soviet Air Defence Forces. Subsequent variations were developed to intercept ballistic missiles.
• The system is one of the more advanced types of weaponry of its kind that can engage multiple aircrafts and ballistic missiles around 90 miles away.
Now get latest Current Affairs on mobile, Download # 1 Current Affairs App