Europe's biggest nuclear power plant has been shelled by Russian forces in Ukraine.
The attack caused a fire to break out, which has since been extinguished.
Ukraine says Russian troops are now in control of the plant.
The International Atomic Energy Agency says radiation levels at Zaporizhzhia do not appear to have changed.
But Ukrainian officials say there's a "real threat of nuclear danger" and if it blows up, it could be 10 times larger than Chernobyl.
Professor M-V Ramana, an expert in nuclear energy, explains why the situation is so dangerous.
Ukraine's president says "only urgent action by Europe" will stop the Russian invasion.
Speaking overnight, Volodymyr Zelenskyy said he fears this is the catastrophe that could lead to the continent's "evacuation".
The UK Ministry of Defence says the port city of Mariupol "remains under Ukrainian control but has likely been encircled by Russian forces".
The city, on the Black Sea, has been "subjected to intense Russian strikes"..
In other developments, more companies are distancing themselves from Russia.
AirBnB's chief executive says it's suspending all operations there and in Belarus.
And Google will stop selling online advertising in Russia.
