The UN nuclear watchdog is preparing to send inspectors in the coming days to two Ukrainian sites at Kyiv's request, it said on Monday.
The International Atomic Energy Agency's announcement followed statements by a senior Russian officer that two institutes in Ukraine linked to the nuclear industry were engaged in preparations to produce such a bomb. "Dirty bombs" are laced with nuclear material.
"The International Atomic Energy Agency (IAEA) is aware of statements made by the Russian Federation on Sunday about alleged activities at two nuclear locations in Ukraine," the IAEA said in a statement, adding that both were already subject to its inspections and one was inspected a month ago, Reuters reported.
"The IAEA is preparing to visit the locations in the coming days. The purpose of the safeguards visits is to detect any possible undeclared nuclear activities and material," it added.
Russian media quoted Lieutenant General Igor Kirillov, head of Russia's nuclear, biological and chemical protection troops, as telling a briefing: "According to the information we have, two organizations in Ukraine are under concrete instructions to create a so-called dirty bomb."
Russia's state news agency RIA had earlier identified what it said were the two sites involved in the operation -- the Eastern Mineral Enrichment Plant in central Dnipropetrovsk region and the Institute for Nuclear Research in Kyiv.