NKorea has vowed to tighten its hold on its "priceless" nuclear deterrent, confounding reports that it might be ready to talk about denuclearisation.
President Mahmoud Ahmadinejad defended Iran's nuclear programme, calling it peaceful and arguing that Tehran has no use for an atomic bomb.
The UN Security Council has held emergency talks on North Korea's third nuclear bomb test in seven years.
Israel's vice prime minister says using cyber-weapons when faced with the threat of a nuclear Iran, would be a "reasonable step".
Deaths of five Iranian nuclear scientists since 2010 a cause for concern.
Russia successfully tested on Friday its two new Bulava intercontinental missiles, which experienced several failures in the past.
Pakistan successfully test fired a medium-range ballistic missile capable of carrying nuclear and conventional warheads, the military said.
Nigeria's foreign minister is threatening action against Iran if it violated international law and UN sanctions in an arms-smuggling case.
It was unlikely that the Israeli government formally offered nuclear weapons to SA in the apartheid era, former foreign minister Pik Botha says.
United States President Barack Obama and Russian leader Dmitry Medvedev signed a landmark nuclear-arms reduction treaty on Thursday.