The Defense Ministry has told the Pentagon that the Israeli Air Force may only purchase 20 Joint Strike Fighters - and not 25 as planned - if the price of the aircraft is significantly higher than $100 million, defense officials said this week. In a Letter of Request (LOR) which the Defense Ministry submitted in July, Israel asked the Pentagon to purchase 25 JSF F-35 stealth fighter jets, but officials said Tuesday that the target date of the beginning of 2010 for a contract would likely not be met. Also known as the Joint Strike Fighter (JSF), the F-35 will be one of the most-advanced fighter jets in the world and will, according to the IAF, significantly boost Israel's deterrence in the Middle East. The JSF is manufactured by Lockheed Martin. Earlier this week, Defense Ministry Dir.-Gen. Pinchas Buhris met with heads of all the major Israeli defense industries and promised that he would continue working with the Americans in an effort to receive approval to integrate as much Israeli technology in the plane as possible. One official who attended the meeting that discussions were held on the possibility that Israel will demand that 50 percent of the electronic technology on the plane be made here. In another move aimed at lowering the price of the aircraft, Israel has also told the Pentagon that it would consider downsizing its initial order if the price increased dramatically. In the negotiations with the Pentagon, 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. In an interview with Defense News earlier this summer, Buhris said: "We understand and appreciate American sensitivities and have adjusted our expectations of this aircraft accordingly. But the gap is still large, the price is still too high. It's unreasonable to expect us to compromise on critical operational needs." The Israeli Air Force had initially hoped to sign a Letter of Agreement (LOA) in the coming months, but officials said that until the differences were resolved and a price was determined the contract would be postponed. If that happens, the arrival of the aircraft - initially slated for 2014 - would also be pushed off.