Iran has no legal grounds to receive damages from Russia over cancellation of a contract to deliver S-300 surface-to-air missile systems, Russian Foreign Minister Sergei Lavrov said.“We have returned the prepayment to them and we believe the issue should be closed,” he said in an interview with Profil magazine.Iran is seeking compensation in international arbitration for breach of the $800 million contract, Defense Minister Ahmad Vahidi said.Russian President Dmitry Medvedev signed a decree banning transfer of S-300 missiles on September 22, 2010, in line with UN Security Council Resolution 1929, which bans supply to Iran of conventional weapons including missiles and missile systems, tanks, attack helicopters, warplanes and ships.