A fire and intense fighting outside a nuclear power plant in Ukraine set off alarm bells around the world on Friday, with worries calmed only slightly by reports that radiation levels had remained stable.

The specter of Russia’s invasion spiraling into a nuclear crisis rattled nerves in Europe and beyond, with Ukrainian President Volodymyr Zelenskyy accusing Moscow of “nuclear terror” and urging the West to intervene to prevent a continent-wide disaster. The incident also served as a reminder of how early reports about an incident — as well as disinformation — can spread confusion and panic in an already chaotic situation.

"No country other than Russia has ever fired on nuclear power units," Zelenskyy said in a video message. "This is the first time in our history. In the history of mankind. The terrorist state has now resorted to nuclear terror."