A top Russian diplomat on Tuesday said that no start date for the delivery of S-300 missiles to Iran has been set yet, according to The Associated Press (AP).
The diplomat added that work is underway to fulfill Russia's supply of the advanced air-defense missiles to the Islamic Republic.
Russian Deputy Foreign Minister Sergei Ryabkov was quoted by the Interfax news agency as saying he could not "say anything for now" about the missiles' delivery date.
The comments come a day after Iran’s Deputy Foreign Minister Hossein Amir-Abdollahian said that Moscow and Tehran have concluded talks on the delivery of the S-300 missiles and that the delivery should take place "quite" soon.
In April, Russian President Vladimir Putin signed a decree lifting a ban on the delivery of S-300 anti-missile rocket systems to Iran.
Russia cancelled a contract to deliver the missile system to Iran in 2010, under pressure from the West following UN sanctions imposed on Iran over its nuclear weapons program. Putin has explained that his decision was motivated by Iran's drive to find a solution in talks over its nuclear program.
Washington has voiced concern over the deal, but Iran hailed the decision as a step towards "lasting security" in the region.
Tehran has previously said the missiles would be delivered by the end of the year, but Russia has denied this and said the delivery of the system “is not a matter of near future.”