The UN's nuclear watchdog is warning of a "very real risk of a nuclear disaster" over military action in Ukraine.
The Prosecutor General's Office in Kyiv says it's started criminal proceedings over rocket and artillery fire at the Zaporizhzhia power plant.
But Russian officials have accused Ukrainian forces of shelling their own facility - saying a radiation leak has been avoided only by luck.
Bernadette Jameson says there are serious concerns over the matter.
"Russia seized Europe's largest nuclear power plant in March and kept its Ukrainian employees," she continued.
"But Kyiv has accused Russian forces of firing rockets at civilian areas from the site.
"The IAEA chief says he is extremely concerned by reports of shelling.
"He warned that military fire power directed at, or from the facility, would amount to playing with fire with catastrophic consequences."