Radioactive water has been leaking from storage tanks at a damaged nuclear power station in Japan, say officials.
The Fukushima power station was badly damaged by an earthquake and tsunami in 2011 and has been shut down.
Water was pumped into the damaged reactors to cool them down - but some of this radioactive water has now escaped from storage containers.
Experts believe that as much as three hundred tonnes of radioactive water has leaked.
Newsround explains: How dangerous is radiation?