A contract on the delivery of advanced S-300 air defense systems to Iran has been stagnated by technical reasons, the Iranian ambassador to Russia said on Thursday.

Russia signed a contract with Iran on the supply of at least five S-300 air defense systems to Tehran in December 2005. However, there have been no official reports on the start of the contract's implementation.

"Iran is ready to receive these systems and our Russian colleagues have assured us that they will meet their obligations," Seyyed Mahmoud-Reza Sajjadi said at a news conference at RIA Novosti in Moscow.

"Several technical issues [in the contract's implementation] have emerged, and we hope they will be resolved soon," the diplomat said without specifying the problems.

Many experts believe Moscow has refused so far to honor the S-300 contract due to pressure from Washington and Tel Aviv.

Both the United States and Israel have not ruled out military action if diplomacy fails to resolve the dispute over Iran's nuclear program and have expressed concern over S-300 deliveries, which would significantly strengthen Iran's air defenses.

Russian defense industry officials have repeatedly said that Russia is interested in fulfilling the contract, which is worth hundreds of millions of dollars, but the future of the contract would largely depend on the current situation in international affairs and the position of the Russian leadership.

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The latest version of the S-300 series is the S-300PMU2 Favorit, which has a range of up to 195 kilometers (about 120 miles) and can intercept aircraft and ballistic missiles at altitudes from 10 meters to 27 kilometers.

It is considered one of the world's most effective all-altitude regional air defense systems, comparable in performance to the U.S. MIM-104 Patriot system.

MOSCOW, February 4 (RIA Novosti)