"The negotiations are continuing, the contract (on the delivery of the S-300 surface-to-air missile defense system to Iran) will be signed in the near future," Sputnik quoted Sergei Ryabkov as saying.
"All political decisions have been made, there are no obstacles there," he added.
Under a contract signed in 2007, Russia was required to provide Iran with at least five S-300 defense system batteries.
In 2010, then-president Dmitry Medvedev cancelled the contract as he came under strong US and Israeli pressure not to go ahead with the sale of the weapons system, but his pretext was that the sale was covered by the fourth round of the UN Security Council sanctions against Iran.
Later, Iran lodged a $4 billion lawsuit at an international court in Geneva against Russia's arms export agency.
Back in April, Russian President Vladimir Putin decided to lift the ban on the S-300 missile system delivery to Iran.