The Federation of American Scientists and the Stockholm International Peace Research Institute, an independent international organization dedicated to researching arms control and disarmament, estimate that Israel has around 90 nuclear warheads.

Due to Israel’s official stance of ambiguity regarding its nuclear program, the organizations note the difficulties in determining the extent of the country’s nuclear capabilities.

“They are intentionally secretive about their nuclear capabilities and that’s part of the policy that they follow,” John Erath, senior policy director at the Center for Arms Control and Non-Proliferation, said in a phone interview Wednesday.

He said that policy was likely in part to ensure Israel’s “potential adversaries would not know what they can do in the event of a crisis.”

How it began

Historical records suggest Israeli leaders had hoped to build a nuclear arsenal to help ensure the country’s safety after it was founded in 1948 in the years after the Holocaust, according to the Jewish Virtual Library, an online encyclopedia published by the American foreign policy analyst Mitchell Bard’s nonprofit organization American–Israeli Cooperative Enterprise.

In a July 1969 declassified memo to President Richard Nixon, Secretary of State Henry Kissinger said that Israel had committed “not to be the first to introduce nuclear weapons into the Near East,” when buying the U.S.’ Phantom aircraft, though it has never been made clear precisely what that means.

Mordechai Vanunu, a former Israeli nuclear technician who worked at Israel’s atomic reactor in Dimona in the Negev Desert in the late 1960s and early 1970s, sent shock waves around the world when he disclosed details and photographs of the reactor to Britain’s Sunday Times newspaper.