MOSCOW - President Vladimir Putin on Monday lifted a ban on supplying Iran with sophisticated S-300 air defence missile systems after Tehran's landmark outline deal with the West over its nuclear programme.
A decree signed by Putin removes a ban on "the shipment from Russia to Iran" of the S-300 missiles, the Kremlin said in a statement.
Moscow blocked deliveries of the surface-to-air missiles to Tehran in 2010 after the United Nations slapped sanctions on Iran over its nuclear programme barring hi-tech weapons sales.
Iran then filed a $4-billion suit at an arbitration court in Geneva for the cancellation of the $800 million order by Russia, which has long been Iran's principal foreign arms supplier.
The decision to lift the delivery freeze comes after Tehran and international powers including Russia made a major breakthrough on April 2 by agreeing an outline deal aimed at curbing Iran's nuclear drive.
The Lausanne framework marked a crucial advance in a 12-year standoff between Iran and the West, which disputes Tehran's denial that it is seeking to build a nuclear bomb.
Russia's Foreign Minister Sergei Lavrov insisted the missile deliveries were not covered by the earlier UN sanctions and that the progress made in Switzerland meant there was no longer any need for Russia to maintain the ban on the missile deliveries.
"We are convinced that at this stage the necessity for a separate and voluntary embargo by Russia has disappeared," Lavrov said in a statement.
Global powers must resolve a series of difficult technical issues by a June 30 deadline for a final nuclear deal, including the steps for lifting global sanctions imposed on Iran, and lingering questions over the possible military dimensions of its nuclear programme.
Iran's Supreme leader Ayatollah Ali Khamenei, who will have the final say on any deal, has plunged the accord into doubt suggesting that "nothing is binding" while President Hassan Rouhani demanded that sanctions be immediately lifted when any deal is signed.
Global powers Britain, China, France, Germany, Russia and the United States have said sanctions will only be gradually eased and want a mechanism to ensure they can be swiftly reimposed if Iran breaks its word.
The initial deal to supply Iran with the S-300 missiles was harshly criticised by the United States and Israel. But Lavrov insisted that the missile system was "exclusively defensive" and said it did not pose a threat to Iran's foes.
"Does not have attack capabilities and does not put any state in the region in danger, including Israel," Lavrov said.
Despite the dispute over the S-300 missiles, Moscow and Iran have remained on good terms, with Russia agreeing to build new nuclear reactors for Tehran and both sides supporting President Bashar al-Assad in Syria.
During a visit by Russian Defence Minister Sergei Shoigu to Tehran in January, Iranian military officials said the two sides had "decided to settle the S-300s problem".
Russia's state arms company said in February that it had offered to supply Iran with Antey-2500 missiles, an upgraded version of the S-300 air defence system that figured in the previous contract.
As Russia has been hit by Western sanctions over its involvement in the conflict in Ukraine, it has stepped up its economic ties with Iran in the past year.