"The contract on delivery of S-300 to Iran has not only been signed by the sides but has already entered into force," Sergei Chemezov said at the Dubai Airshow-2015.
He added that as soon as the first part of the contract is fulfilled, then Iran would rescind its court case against Russia for the non-delivery of the system, basically due to economic sanctions that were in place against Tehran.
Chemezov didn't elaborate exactly which variations of the S-300 missile defense systems will be supplied to Iran.
Moscow and Tehran signed an $800-million deal for the delivery of five S-300 missile systems in 2007. In 2011, Iran sued Russia in the Geneva Arbitration Court after Moscow suspended the contract in 2010, citing a UN Security Council resolution that placed an arms embargo on Tehran.
Russian President Vladimir Putin lifted the S-300 delivery ban in April 2015, shortly after the P5+1 group of international negotiators and Iran reached a framework nuclear agreement to remove all economic sanctions against Tehran in exchange for its pledge to ensure that all nuclear research in the country will be for peaceful purposes.