Iran's defence minister on Tuesday met his Russian counterpart with the reported aim of persuading Moscow to deliver sophisticated air-defence missiles at a time of mounting tension with the West.

Mostafa Mohammad Najjar met his Russian counterpart, Anatoly Serdyukov, in "constructive" talks which looked at present and future Russian-Iranian defence relations, the Russian defence ministry said.

Najjar was expected to urge Moscow to fulfill a controversial contract for the delivery of Russian S-300 anti-aircraft missile systems to Tehran, Russian news agencies and newspapers reported.

"It is not ruled out that during the talks the Iranian side will raise the question about fulfilling the contract for the delivery of the S-300," the Interfax news agency quoted a military source as saying.

Also expected to be raised was the question of after-sales service for the 29 Tor-M1 missile systems that Russia sold to Iran in 2005 for a reported 700 million dollars, Interfax said.

"I hope that this visit will lead to long-term development of relations in military cooperation, security and the strengthening of security in the region and around the world," Najjar said, according to an Iranian embassy statement.

The statement made no mention of possible discussions about the weapons.

The fulfillment of the S-300 contract -- reported to have been signed some time ago -- is particularly controversial as such weapons could significantly upgrade Iranian air-defence capabilities.

The Tor-M1 air-defence systems have a shorter range than the sophisticated S-300s.

The United States has never ruled out the option of a military strike against the Islamic republic over its contested nuclear drive, which Western powers fear could be aimed at making an atomic bomb.

But the Kommersant newspaper cited unnamed sources as saying Russia was unwilling to supply the weapons at a time when it wants to improve relations with the new US administration of President Barack Obama.

"The main restraining factor in the development of defence relations with Iran is the possibility for Moscow to improve its relations with the United States," it said.

"News even just about the start of deliveries would seriously darken the atmosphere of these negotiations," it said.

The next weeks will be crucial for the development of relations. Russian Foreign Minister Sergei Lavrov confirmed on Tuesday he expected to meet new US Secretary of State Hillary Clinton in the next two weeks.

The head of the state arms export agency Rosoboronexport has said that a political decision was required before the S-300 arms systems could be delivered to Tehran.

"If there is a decision from the president, a decision from the Russian government then Rosoboronexport will be obliged to fulfill it," Anatoly Isaikin said in an interview with the Nezavisimaya Gazeta earlier this month.

Rosoboronexport spokesman Vyacheslav Davydenko told AFP Tuesday the situation had not changed since those comments were made.

Russian officials denied press reports in December that it had begun delivering these sophisticated surface-to-air missiles to Iran.