Russia is negotiating the delivery of more air defense systems to Iran despite Western demands for a halt in sales to Tehran over its refusal to stop uranium enrichment, the head of Russia''s arms exporter said Thursday.

"Contacts between our countries [on delivery of air defense systems] are continuing and we do not see any reason to suspend them," Rosoboronexport General Director Anatoly Isaikin told reporters at the Africa Aerospace & Defence-2008 (AAD-2008) exhibition near Cape Town in South Africa.

The official reiterated that deliveries of Russian anti-aircraft weaponry to Iran were aimed exclusively at increasing its air defense capability and were not subject to international restrictions.

Iran recently took delivery of 29 Russian-made Tor-M1 air defense missile systems under a $700-million contract signed in late 2005. Russia has also trained Iranian Tor-M1 specialists, including radar operators and crew commanders.

The U.S. and Israel, which have consistently refused to rule out the possibility of military action against Iran, were alarmed by media reports, which started circulating as early as 2005, on the possible delivery of S-300 surface-to-air missiles to Iran, as these systems could greatly improve Iranian defenses against any air strike on its strategically important sites, including nuclear facilities.