South Korea has responded to an apparent nuclear test by North Korea by carrying out its own missile drills.

The UN Security Council will meet later - as US Defence Secretary James Mattis warns any threat to America or its allies will be met with a massive military response.

On Sunday, Kim Jong Un's regime said North Korea's sixth nuclear test was a "perfect success" and involved a bomb designed to be mounted on its newly developed intercontinental ballistic missile.

Despite tough talk from the US, the immediate response from the international community is likely to focus on enforcing even tougher economic sanctions on the isolated state.

According to diplomats, the UN could consider banning North Korea's national airline and textile exports from Pyongyang, as well as halting the supply of oil to its government and military.