With a defiant nuclear test, North Korea has shown it poses an increasingly credible threat but some doubt whether even the notoriously bellicose regime would ever use weapons of mass destruction.
Britain on Tuesday strongly condemned North Korea's announcement that it has staged its most powerful nuclear test yet and called for a "robust response" from the UN Security Council.
North Korea staged an apparent nuclear test Tuesday in a striking act of defiance that, if confirmed, is sure to trigger global condemnation from enemies and allies alike.
Iran faces possible referral to the UN Security Council in early March unless Tehran and the UN atomic agency defy expectations in talks Wednesday and reach a deal on enhanced inspections.
UN leader Ban Ki-moon warned Thursday that a nuclear test by North Korea could blow up hopes of an eventual reconciliation by "tying the hands" of the South's incoming president.
The United States on Wednesday tightened sanctions on Iran to further choke off its oil income, saying it was necessary to increase pressure on Tehran over its suspected nuclear weapons program.
North Korea's expected atomic test will offer a rare chance to gauge where its nuclear programme is headed, with most expert attention focused on what type of device is detonated and how.
North Korea has vowed to carry out a third nuclear test, but scientists and concerned foreign governments may have a tough time verifying the actions of the reclusive state.
Agreeing a venue for the next round of talks between Iran and six world powers on Tehran's nuclear drive was hard enough. Achieving progress will be tougher still.
Iranian Foreign Minister Ali Akbar Salehi said on Sunday that fresh talks with world powers on Iran's nuclear drive would be held in Kazakhstan on February 25.
South Korea and the United States launched a joint naval exercise involving a US nuclear submarine Monday, as tensions rise on the Korean peninsula ahead of an expected nuclear test by North Korea.
North Korea has covered the entrance to a tunnel at its nuclear test site in an apparent effort to avoid satellite monitoring ahead of a widely expected detonation.
South Korean President Lee Myung-Bak held an emergency security meeting Thursday that warned North Korea of "serious consequences" if it went through with an expected nuclear test.