Iran announced Wednesday that Russia will provide Iran with the sophisticated and powerful S-300 anti-aircraft missile defense system, vastly improving the Islamic Republic's ability to protect its nuclear development facilities.

"The S-300 air defense system will be delivered to Iran on the basis of a contract signed with Russia in the past," said Iran's Defense Minister Mostafa Mohammad Najjar, according to Iranian state television.

The missiles can intercept targets at an altitude of up to 27 kilometers (90,000 feet) and at ranges of up to 150 kilometers (95 miles) from the launch point. They are effective against cruise missiles and ballistic warheads as well, and are equivalent to the PAC-3 Patriot missiles which Israel is considering purchasing.

Russian military officials contend that the S-300 is of a higher operational standard than the U.S.-built Patriot missiles currently used by Israel.

The S-300 systems are also a major improvement over the 29 Tor-M1 air defense missile systems delivered to Iran from Russia earlier this year. The $700 million contract for that purchase was signed in December 2005. Former Israel Air Force Commander Eitan Ben-Eliyahu told Channel 10 TV that the missiles will make it significantly harder for Israel to attack Iran from the air, if it chooses to do so.

Even aircraft that do not directly participate in the attack will be endangered by the missiles, he said, adding that AWACS planes, standby rescue planes and other planes with protective missions could be targeted by such long range missiles.

Najjar did not specify how many S-300 systems would be shipped to Iran, nor did he say when this would happen. An unidentified Russian source confirmed that dozens of S-300 batteries would be transferred to Iran and that the contract had already been signed several years ago.