"The Iranian side will withdraw its lawsuit as soon as the contact takes effect and we are in full compliance with our liabilities," Anatoly Isaikin said on Tuesday, Russia's news agency Tass reported.
“The completion of the contract on the S-300 missile system for Iran was suspended and we’ve been given the order to renew work and as the executors, we are doing this, but much time has gone by and the S-300 system has changed so we’re working on the modernization of the system,” 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 which is now pending review.
However, Russian President Vladimir Putin decided in April this year to lift the ban on the S-300 missile system delivery to Iran.