Russian President Vladimir Putin defended on Tuesday Russia’s right to sell arms to the Syrian government but said Moscow had not yet delivered advanced S-300 air defense systems to Damascus.

Although Western governments have criticized Russia for planning to send the missile systems to President Bashar al-Assad’s forces, Putin told a news conference the contracts were legal and were not intended to upset the military balance.

He also praised the S-300 missiles system as one of the best in the world but added: “The contract was signed several years ago. It has not been fulfilled yet.”

Russia has said it is committed to sell the S-300 surface-to-air missiles as a deterrent against foreign military intervention, under a contract struck in 2010 with Assad.

Putin also said after a summit with European Union leaders in the city of Yekaterinburg that any foreign military intervention in Syria's more than two-year-old civil war was doomed to fail and could make the situation in Syria worse.

He also criticized an EU decision not to extend an embargo on member states arming rebel forces fighting the Syrian government.