A senior Russian official said Wednesday the delivery of S-300 air defense missiles to Iran has been delayed for unspecified technical reasons, Interfax news agency reported.

Russia will deliver the surface-to-air missiles to Iran after the technical flaws have been repaired, Interfax quoted Alexander Fomin, deputy head of Russia's Federal Service for Military-Technical Cooperation, as saying.

"The delay is due to technical problems. The systems will be delivered when these problems have been resolved," Fomin said without providing details.

Fomin spoke with Interfax while attending a defense exhibition in New Delhi, India.

The S-300 defense system is an advance mobile system that can travel at more than 2 km per second and can shoot down aircraft and cruise missiles from up to 150 km away.

The United States and Israel were trying to persuade Russia not to sell the missile system to Iran because it could foil attempts to hit the country's nuclear facilities with an airstrike.

Russia on Tuesday joined the United States and France in criticizing a new push by Iran to step up its uranium enrichment, and Moscow said it did not exclude a new round of sanctions against Iran.

Israeli Prime Minister Benjamin Netanyahu visited Moscow this week, lobbying Moscow to support new sanctions.

Russia and Iran reached a contract for the missile system in 2007.