Israel has 80 nuclear warheads and the potential to double that number, according to a report by US experts. While it stopped production of nuclear warheads in 2004, the country had enough fissile material for an additional 115 to 190 warheads, the report claimed. The report was written by proliferation experts Hans Kristensen and Robert Norris in the Global Nuclear Weapons Inventories , recently published in the Bulletin of the Atomic Scientists . Previous estimates have been higher, but the new figures agree with the Stockholm International Peace Research Institute yearbook on armament and international security. The yearbook estimated 50 of Israel's nuclear warheads were for medium-range ballistic missiles and 30 were for bombs carried by aircraft, according to a report in The Guardian . Although widely assumed a nuclear power, Israel has never acknowledged that it possesses nuclear weapons or capabilities. It continues to maintain its decades-old "strategic ambiguity" policy on the matter, neither confirming nor denying foreign reports on the issue. In 1986, Mordechai Vanunu, an Israeli nuclear technician, leaked the country's alleged nuclear secrets to a British newspaper and said Israel had at least 100 nuclear weapons. Vanunu was later convicted of espionage and treason and was released from jail in 2004 after serving 17 years. Israel continued to adhere to its vagueness policy after comments made by prime minister Ehud Olmert in 2006 were interpreted by many as an inadvertent confirmation that Israel had nuclear weapons. Following Sunday's reports, Israeli defence analyst Amir Oren said the ambiguity policy had done "its duty honourably and can now retire". In the current regional conditions, Israel could benefit from giving up the vagueness, he added. Israel is not a party to the Treaty on the Non-Proliferation of Nuclear Weapons and in 2010 dismissed a demand from the parties to join.