The North Korea crisis in 300 words
The North Korean stand-off is a crisis that, at worst, threatens nuclear war, but it's complicated. Let's take a step back.
Why does North Korea want nuclear weapons?
The Korean peninsula was divided after World War Two and the communist North developed into a Stalinesque dictatorship.
Almost entirely isolated on the global stage, its leaders say nuclear capabilities are its only deterrent against an outside world seeking to destroy it.
How close are they?
North Korea's latest missile tests suggest they have an intercontinental ballistic missile (ICBM) capable of reaching the US.
They have tested nuclear devices five times. Intelligence reports warn the country is also close to, or has already achieved, "miniaturisation" - developing a nuclear warhead small enough to fit on a rocket.
Pyongyang views the US as its main adversary but also has rockets aimed at South Korea and Japan, where thousands of US troops are based.
What has been done to stop them?
Attempts to negotiate aid-for-disarmament deals have repeatedly failed.
The UN has implemented increasingly tough sanctions - to little effect. China, the North's only real ally, has also put economic and diplomatic pressure on the North.
The US has now threatened military force with President Donald Trump warning of "fire and fury".
Is it for real this time?
The crisis has been brewing for years, but miniaturisation and the US being within reach of a strike are both game changers.
Pyongyang on Wednesday said it was considering missile strikes near the US Pacific territory of Guam.
Nuclear confrontation seems more real than ever, but is still far from a certainty.