Moscow, July 11 (RIA Novosti) Israel has ordered at least 25 US F-35 stealth fighter aircraft to counter any potential threat from the delivery of Russian advanced air defence systems to Iran and Syria, an Israeli daily said.

Tel Aviv earlier said the purchase of F-35 fighters would effectively eliminate the threat from Russian-made S-300 air defence systems because a series of computer simulations had clearly demonstrated that new US stealth fighters outperform the Russian missiles.

The F-35 Joint Strike Fighter (JSF), manufactured by Lockheed Martin, 'will be one of the most-advanced fighter jets in the world and will enable Israel to phase out some of its older F-15 and F-16 models', the Jerusalem Post said Friday.

The paper said an official Letter of Request (LOR) to the Pentagon was sent this week, but talks on a final price for the plane, estimated at over $100 million, and technical details of the deal would continue.

'Israeli demands have focused on three issues - the integration of Israeli-made electronic warfare systems into the plane, the integration of Israeli communication systems and the ability to independently maintain the plane in the event of a technical or structural problem,' it said.

The contract is expected to be signed in early 2010 followed by the delivery of the first F-35 fighters to Israel in 2014.