South Koreans burn pictures of North Korean ruler Kim Jong-eun after Pyongyang's nuclear test. (AP)

North Korea’s decision to conduct its third underground nuclear test will come as no surprise to governments around the world. Pyongyang has been making clear for some weeks that it planned a nuclear test at a “higher level” than its previous two in 2006 and 2009. Its decision to press ahead has already triggered widespread condemnation from the US and its allies. Now that the test has taken place, diplomats and nuclear experts will be asking four key questions about the nuclear explosion.

First, have the North Korans managed to developed a device that they can place on top of a long-range missile?

North Korea stated that the test used “a small and lighter nuclear device with greater explosive force than previously”. This will prompt fears that Pyongyang has managed to miniaturize a nuclear warhead, in order to place it on top of a long range ballistic missile. Read more