The head of the UN nuclear agency flew to Tehran on a delicate mission that - if successful - could finally lift the veil on whether Iran is seeking atomic arms while strengthening the Islamic Republic's negotiating hand in crucial nuclear talks with six world powers later in the week.

The crushing primary defeat of Indiana’s veteran Republican senator Richard Lugar not only shows the Tea Party movement is alive and well. It is also a pointer that the next Congress will be even more partisan and less inclined to compromise than ever.

A UN nuclear inspector from South Korea was killed today and a colleague was injured in a car crash near a reactor site in central Iran, the nuclear watchdog agency said.

Analysts who have studied photos of a half-dozen ominous new North Korean missiles showcased recently at a lavish military parade say they were fakes, and not very convincing ones, casting further doubt on the country's claims of military prowess.

George Cowan, who died on 20 April aged 92, was a chemist who influenced everything from the Manhattan Project and the hunt for evidence of the Soviet Union's first nuclear tests to the Santa Fe Opera. After graduate studies at Princeton, Cowan continued his nuclear research as part of the Manhattan Project that developed the atomic bomb. Cowan was a troubleshooter for the effort at various research sites around the country and was among the few people who had knowledge of the bomb's separate components.

Six world powers and Iran are meeting in an attempt to find common ground over concerns that Tehran's nuclear programme could be used to make weapons.

A prominent Iranian politician has for the first time publicly declared that Iran has the ability to produce nuclear weapons, but will never do so.

A prominent Iranian lawmaker has said Iran has the knowledge and scientific capability to produce nuclear weapons but will never do so.

Shares in the engineer Redhall Group crashed 21 per cent yesterday after it issued a profits warning due to problems with its £20m deal to make blast-proof doors for the building housing Britain's nuclear warheads.

Britain has denied sending a nuclear-armed submarine to the South Atlantic amid rising tensions with Argentina over the Falklands.

Nick Clegg today underlined Britain's "commitment to fostering stronger trade links" with the world's fastest growing economies as he announced the UK had approved a Free Trade Agreement between the EU and Korea during his visit to South Korea.

President Barack Obama will visit the Demilitarised Zone separating North and South Korea next week.

Amid new tension with North Korea over a planned rocket launch, President Barack Obama plans to visit the Demilitarized Zone separating North and South Korea at the start of an international trip next week, the White House said.