President Barack Obama tells a nuclear summit in the US that the threat of a nuclear terrorist attack persists and the world must be resolute in foiling it. More than 50 nations were represented at the summit.

North Korea fires another short-range missile off its east coast on Friday, South Korean officials said, as regional leaders met in Washington to discuss the threat of Pyongyang's nuclear weapons programme.

President Vladimir Putin says Russia will add more than 40 intercontinental ballistic missiles to its nuclear arsenal in 2015.

US President Obama hails a deal restricting Iran's nuclear programme as a "historic understanding" which, if implemented, will make world safer.