States with nuclear weapons

With its first nuclear test under its belt, North Korea has joined a small group of countries that have tested a nuclear weapon. That includes, the United States, USSR, UK, France, China, India and Pakistan. Wikipedia has an interesting entry on the countries with nuclear weapons. From Wikipedia:

* The United States of America developed the first atomic weapons during World War II out of the fear that Nazi Germany would develop them first. It tested its first nuclear weapon in 1945 ("Trinity"), and remains the only country to have used nuclear weapons against another nation, during the atomic bombings of Hiroshima and Nagasaki (see: Manhattan Project). It was the first nation to develop the hydrogen bomb, testing it ("Ivy Mike") in 1952 and a deployable version in 1954 ("Castle Bravo").

* The USSR tested its first nuclear weapon ("Joe-1") in 1949, in a crash project developed partially with espionage obtained during and after World War II (see: Soviet atomic bomb project). The direct motivation for their weapons development was the development of a balance of power during the Cold War. It tested a primitive hydrogen bomb in 1953 ("Joe-4") and a megaton-range hydrogen bomb in 1955 ("RDS-37"). The Soviet Union also tested the most powerful explosive ever detonated by humans, ("Tsar Bomba"), which had a yield of 100 megatons, but was intentionally reduced to 50. After its dissolution in 1991, its weapons entered officially into the possession of Russia Russia.

* The United Kingdom tested its first nuclear weapon ("Hurricane") in 1952, drawing largely on data gained while collaborating with the United States during the Manhattan Project. Its program was motivated to have an independent deterrence against the USSR, while also remaining relevant in Cold War Europe. It tested its first hydrogen bomb in 1957. It maintains the Trident fleet of nuclear weapon submarines.

* France tested its first nuclear weapon in 1960, also as an independent deterrence and to retain perceived Cold War relevance (see: Force de frappe). It tested its first hydrogen bomb in 1968.

* The People's Republic of China tested its first nuclear weapon in 1964, much to the surprise of Western intelligence agencies. It had long sought assistance in becoming a nuclear power from an uneasy USSR, but assistance stopped after the Sino-Soviet split and the weapon was developed as a deterrent against both the USA and the USSR. It tested its first hydrogen bomb in 1967 at Lop Nur. The country is currently thought to have had a stockpile of around 130 warheads, potentially less.

* India is not a member of the Nuclear Non-Proliferation Treaty, but tested a "peaceful nuclear device", as it was described by the Indian government, in 1974 ("Smiling Buddha"), the first test developed after the creation of the NPT, and created new questions about how civilian nuclear technology could be diverted secretly to weapons purposes (dual-use technology). It appears to have been primarily motivated as a deterrent against China[citation needed]. It tested weaponized nuclear warheads in 1998 ("Operation Shakti"), including a Hydrogen Bomb. In July 2005, it was officially recognized by the United States as a responsible nuclear state and agreed to full nuclear cooperation between the two nations. This is seen as a tacit entry into the nuclear club of the above nations.

* Pakistan is not a member of the Nuclear Non-Proliferation Treaty. Pakistan covertly developed nuclear weapons over many decades, beginning in the late 1970s. Pakistan first delved into nuclear power after the establishment of it's first nuclear power plant near Karachi with the help of Canada in the early 70s. After the detonation of a nuclear bomb by arch rival India, the country gradually started it's own nuclear weapons development program and established secret, mostly underground, nuclear facilities near the capital Islamabad. It is believed that Pakistan already had nuclear weapons capability by the end of the 1980s. However, this was to remain speculative until 1998 when Pakistan conducted its first nuclear tests at the Chagai Hills, a few days after India conducted its own tests.

* North Korea has performed its first-ever nuclear weapons test. The nuclear test was conducted at 10:36 am (0706 IST) in Hwaderi near Kilju city Monday, October 9, 2006.