U.S. President Barack Obama set out his vision for a world free of nuclear weapons Sunday, vowing to involve all states with atomic weapons in the process of reducing arsenals.
Here are details of official and unofficial nuclear powers and their arsenals:
OFFICIAL NUCLEAR POWERS:
* UNITED STATES: According to the counting rules in the Strategic Arms Reduction Treaty (START), as of January 2009, the United States had an estimated 5,200 nuclear warheads and 2,700 operationally deployed warheads (2,200 strategic and 500 nonstrategic warheads).
-- According to the May 2002 Treaty of Moscow (the Strategic Offensive Reductions Treaty, or SORT) between the United States and the Russian Federation, both are required to reduce their nuclear arsenals to 1,700-2,200 operationally deployed warheads by 2012.
* RUSSIA: Under the provisions of the START I, the Russian nuclear arsenal has been reduced to approximately 4,138 strategic nuclear warheads, as of July 2008.
* FRANCE: France has been a nuclear weapon state party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since 1992. In 2008, French President Nicolas Sarkozy announced that the country would leave its submarine missile arsenal in place while cutting its stock of air-launched weapons by a third.
-- As of September 2008, France had already pared down its arsenal to approximately 300 nuclear warheads.
* BRITAIN: The United Kingdom's current nuclear stockpile consists of fewer than 200 strategic and "sub-strategic" warheads on four Vanguard-class nuclear-powered ballistic missile submarines.
* CHINA: China's nuclear weapons program began in 1955 and culminated in a successful nuclear test in 1964. Since then, China has conducted 45 nuclear tests, including tests of thermonuclear weapons and a neutron bomb.
-- China is estimated to have about 400 strategic and tactical nuclear weapons, and stocks of fissile material sufficient to produce a much larger arsenal. It acceded to the NPT in 1992 as a nuclear weapon state.
OTHER "DECLARED" NUCLEAR NATIONS:
* NORTH KOREA: North Korea has only undertaken one test of a nuclear device which took place in October 2006 and occurred after Pyongyang withdrew from the NPT.
-- Six-Party Talks between North Korea, South Korea, Japan, China, Russia, and the United States began in 2003 to quell North Korea's nuclear ambitions but broke down in 2005.
-- Talks were resumed in 2007 and in June 2008 it presented a long-delayed list of its nuclear arms programs. However North Korea said late last month it would restart its nuclear plant that makes arms-grade plutonium if the United Nations punished it for a satellite launch which took place Sunday.
* INDIA: India has formally declared itself a nuclear weapon state. New Delhi is likely to have manufactured weapons grade plutonium for at least 100 warheads. A 2007 report from the International Panel on Fissile Materials estimated that 50-60 warheads had been assembled so far. Neither India or Pakistan are signatories to the NPT.
* PAKISTAN: Pakistan is believed to have stockpiled approximately 580-800 kg of highly enriched uranium, sufficient amounts to build 30-50 fission bombs. According to the United States, China helped Pakistan by providing nuclear-related materials, scientific expertise, and technical assistance. The Bulletin of the Atomic Scientists, estimated in 2007 that the Pakistani arsenal comprised about 60 warheads.
OTHER UNDECLARED NATIONS:
* ISRAEL: Israel is widely understood to possess a sizeable nuclear arsenal, but it maintains a policy of nuclear ambiguity.
-- Based on estimates of the plutonium production capacity of the Dimona reactor, Israel has approximately 100-200 advanced nuclear explosive devices. Officially, Israel has declared that it will not be the first to introduce nuclear weapons into the Middle East. Israel has not signed the NPT treaty.
* IRAN: Iran has been a non-nuclear weapon state party to the NPT since 1970, and has had a nuclear program, ostensibly for peaceful purposes. However its nuclear program has advanced significantly in the past decade with Iran's decision to enrich its own uranium.
-- Iran says it needs nuclear energy so that it can export more of its huge oil and gas reserves. Its refusal to halt nuclear work which can have both civilian and military purposes has drawn three rounds of limited U.N. sanctions since 2006. Sources: Reuters/ www.nti.org (Nuclear Threat Initiative)
(Reporting by David Cutler, London Editorial Reference Unit)