High Quality Content by WIKIPEDIA articles! Israel is widely believed to be the sixth country in the world to have developed nuclear weapons and to be one of four nuclear-armed countries not recognized as a Nuclear Weapons State by the Nuclear Non-Proliferation Treaty (NPT), the others being India, Pakistan and North Korea. Former International Atomic Energy Agency Director General Mohamed ElBaradei regarded Israel as a state possessing nuclear weapons, but Israel maintains a policy known as "nuclear ambiguity" (also known as "nuclear opacity"). Israel has never officially admitted to having nuclear weapons, instead repeating over the years that it would not be the first country to "introduce" nuclear weapons to the Middle East, leaving ambiguity as to whether it means it will not create, will not disclose, will not make first use of the weapons or possibly some other interpretation of the phrase. The "not be the first" formulation goes back to before March 11 1965, when a cable from the US Embassy in Tel Aviv to Washington noted "The Government of Israel has reaffirmed that Israel will not be the first to introduce nuclear weapons into the Arab-Israel area." Israel has refused to sign the NPT despite international pressure to do so, and has stated that signing the NPT would be contrary to its national security interests.