Investigators have found nuclear contamination tens of thousands of times above safe levels on the premises of a ruined factory in Russia's Chechnya, officials said on Saturday.
It was not clear why the radioactive source had been kept in the factory, but prosecutors said it posed a severe threat to anyone who came near to it.
"This is above all now a threat to the population, because the leadership and officials of the firm did not take the necessary steps to isolate the isotope," said Chechen prosecutor Valery Kuznetsov on NTV television.
Almost all of Grozny was destroyed by Russian bombing in 1999-2000 when Russian troops poured back into the region to reassert central control over separatist rebels, who still attack troops and police daily.
Once a mighty industrial centre, Grozny's factories are now a wasteland of twisted steel - many of them dotted with machine gun nests. Other Chechen officials did not wish to comment on the presence of the radioactive material, which was named by the prosecutors as Cobalt-60 - a variation of cobalt used as a source of radiation in food processing, hospitals and elsewhere.
Prosecutors said it had raised radiation levels to 58,000 times above normal.