On September 3, 2017 North Korea tested its latest nuclear weapon, which was estimated to be up to eight times more powerful than the atomic bomb dropped on Hiroshima.

The underground explosion at the Punggye-ri test site in the far northeast of the hermit kingdom caused earth tremors that could be felt across the border in China and as far away as Russia’s eastern sea port of Vladivostok.

Here's how North Korea’s weapon development programme compares with those of other nuclear-armed nations.