El-Baradei also paid tribute to the victims of the disaster, the world's worst nuclear accident, which happened exactly 20 years ago today.
The UN nuclear watchdog has been accused in the past of downplaying the true extent of the Chornobyl disaster.
Click on the map to enlarge.
NOT JUST A LOCAL PROBLEM: On April 27, 1986, the day after the explosion at Chornobyl, workers at Sweden's Forsmark Nuclear Power Plant were found to have radioactive particles on their clothes, which led to a search for the source, and the first suspicions that a nuclear accident had occurred in the Soviet Union.
The cloud of radioactive particles from Chornobyl passed over Scandinavia, the Netherlands, Belgium, and the British Isles, before the wind changed, after which it was blown south over much of Europe. Radioactive contamination from the Chornobyl disaster was also detected as far away as North America and Japan.