MOSCOW (Bloomberg) - President Vladimir Putin lifted a ban on the delivery of S-300 air-defense missile systems to Iran as Russia pushed for repeal of an arms embargo following an agreement on the Islamic republic's nuclear programme.

Putin repealed its 2010 prohibition on S-300 exports to Iran, the Kremlin said Monday in a statement on its website. While the two countries had signed an US$800 million (S$ 1.09 billion) contract for the systems in 2007, Russia halted delivery after the United Nations imposed an arms embargo three years later.

The S-300 is a "purely defensive" weapon and delivering it to Iran won't "threaten the security of any state in the region, including, of course, Israel," Russian Foreign Minister Sergei Lavrov said Monday, the Interfax news service reported.

Iran and representatives of Russia, the U.S., China, France, Germany and the U.K. announced on April 2 in Switzerland that they'd negotiated a political framework to resolve the confrontation over the Islamic republic's nuclear program that restricts it to civilian use and can't be used to build a bomb. Iran denies it's seeking to develop nuclear weapons. A final agreement must be negotiated by June 30.

Lavrov and U.S. Secretary of State John Kerry spoke by phone and discussed "further steps by the international community on Iran in light of the progress reached in talks on the situation around Iran's nuclear program," Russia's Foreign Ministry said in a website statement.

Repealing the UN arms embargo "will require serious diplomatic efforts and political decisions," and should be the first step taken after the conclusion of the agreement on Iran's nuclear program, Russian Deputy Foreign Minister Sergei Ryabkov said, according to the Tass news service.

Russia "will promptly carry out the order of the president" and send the S-300 systems to Iran "if a political decision is taken" to deliver them, Interfax reported, citing the Defense Ministry in Moscow.