Nuclear, Nuclear Weapon | featured news

China's leaders issued thinly veiled rebukes to North Korea for raising regional tensions, with the president saying no country should throw the world into chaos and the foreign minister warning that Beijing would not allow mischief on its doorstep.

An air of cautious optimism hung over Almaty, Kazakstan, on Friday as Western and Iranian negotiators began another round of nuclear talks. The six powers – the United States, Russia, China, France, Britain and Germany – met Iranian officials with the aim of settling a decade-long tussle over Tehran's nuclear program.

North Korea's vow to restart its mothballed nuclear facilities raises fears about assembly lines churning out fuel for a fearsome arsenal of nuclear missiles. But it may actually be a sign that Pyongyang needs a lot more bomb fuel to back up its nuclear threats.

Defense Secretary Chuck Hagel is calling North Korea's development of nuclear weapons a "growing threat" to the U.S. and its allies. In a telephone call Tuesday evening to Chinese Defense Minister Chang Wanquan, Hagel cited North Korea's pursuit of nuclear weapons and ballistic missiles and said Washington and Beijing should continue to cooperate on those problems.

Pyongyang’s warning that it will step up its uranium enrichment comes two days after the country’s leader called for expanding his country’s nuclear arsenal both in “quality and quantity.”

North Korea said on Saturday it was entering a "state of war" with South Korea in a continuing escalation of tough rhetoric against Seoul and Washington after coming under international sanctions for its nuclear test.

The barrage of threats from North Korea has sparked talk from within South Korea of the need to develop its own nuclear weapons. A recent poll shows that two-thirds of South Korean citizens surveyed support the idea, especially in the wake of North Korea's third nuclear test in February.

North Korea threatened the United States on Thursday with a preemptive nuclear strike, raising the level of rhetoric while the U.N. Security Council considers new sanctions against the reclusive country.

The U.N. nuclear watchdog raised pressure on Iran to finally address suspicions that it has sought to design an atomic bomb, calling for swift inspector access to a military base where relevant explosives tests are believed to have been carried out.

Lyse Doucet assesses Iran's change in tactics at the latest nuclear talks in Almaty, Kazakhstan.