NEW YORK — Diplomats from almost every nation will convene in New York for a four-week review conference of the Treaty on the Non-Proliferation of Nuclear Weapons. The treaty has 190 member states.

The treaty entered into legal force in 1970 for an initial period of 25 years and was indefinitely extended in 1995. Review conferences have been held every five years since 1995, producing agreed outcome documents only twice, in 2000 and in 2010.

At the 2000 conference, members agreed to 13 practical steps to progress nuclear disarmament, which remain almost completely unimplemented. At the 2010 conference, members agreed to a 64-point action plan, with variable implementation, particularly for 22 actions related to disarmament. At the 2015 conference, Canada, the United Kingdom and the United States blocked adoption of a negotiated review conference text at the behest of Israel. At the 2022 conference, Russia blocked adoption of the final text due to references to the Zaporizhzhia nuclear power plant in Ukraine.

"It may not put an end to the NPT itself but it may hollow out the NPT. We may lose the credibility of the NPT itself." conference president Do Hung Viet said ahead of the gathering.

China, France, Russia, the U.K. and the U.S. manufactured and exploded nuclear weapons before 1967. All other members of the treaty do not have nuclear weapons. North Korea joined the treaty and then renounced it. India, Israel, Pakistan and South Sudan have never joined. Canada, Germany, Sweden, Switzerland, South Korea and Australia gave up nuclear weapons programs or ambitions after joining.

Nine states possess nuclear weapons, and all are investing in modernising their arsenals with more capable and dangerous weapons. The number of deployed nuclear weapons and those on high alert ready to be launched within minutes is rising. The Doomsday Clock is closer to midnight than it has been since 1947.

Russia and the U.S. account for nearly 90% of the world's nuclear weapons. The last remaining bilateral agreement constraining Russian and U.S. nuclear weapons lapsed in February with no replacement.

Russian forces attacked and damaged nuclear facilities in Ukraine, interfered with their operation, used some as military bases, and jeopardised the power and water supplies critical to cooling reactors and spent fuel ponds, risking a radiological disaster extending beyond Ukraine's borders. The 2022 review conference did not pass any measures to protect nuclear facilities from attack. The U.S. and Israel carried out attacks on Iran's nuclear facilities, citing Iran's imminent acquisition of nuclear weapons as justification. The head of the International Atomic Energy Agency said that Iran was not imminently acquiring nuclear weapons.