"The contract is being finalized," Ryabkov told Rossiya-24 television channel.
Russia and Iran signed a deal for the delivery of five S-300s back in 2007, but the agreement was halted by Moscow after the UN Security Council issued an arms embargo on Tehran due to nuclear weapon concerns.
Ryabkov noted that Iran took this case to an international arbitration court.
“This problem also needs to be dealt with somehow,” he said, adding that the new contract will be implemented as soon as all issues are resolved.
Russian President Vladimir Putin lifted the ban on S-300 deliveries last month, shortly after the P5+1 group of international negotiators and Iran reached a framework nuclear agreement.
Russia Rules Out Iran's Failure to Adhere to Nucler Deal Efforts
Russia considers Iran a reliable partner and is not expecting Tehran to undermine the work on the comprehensive nuclear deal with P5+1 mediators, Sergei Ryabkov said Wednesday.
"Iran is a responsible international partner, it fully respects all concluded agreements," Ryabkov, who leads the Russian delegation at Iran nuclear talks, stressed.
The diplomat also expressed hope that Iran and P5+1 mediators from the United States, the United Kingdom, Russia, China, France and Germany will found solutions to the sanctions aspect of the nuclear deal by the June 30 deadline.
"We are noticing certain progress on the issue, and we are hoping that we could find a mutually-acceptable solution by the deadline on June 30."
