Russian forces have captured the Chernobyl nuclear power plant, an adviser to Ukraine's presidential office, Mykhailo Podolyak, said Thursday.
"It is impossible to say that the Chernobyl nuclear power plant is safe after a completely senseless attack by the Russians. This is one of the biggest threats in Europe," Podolyak said.
Before entering Ukraine early Thursday, some Russian military personnel gathered in the Chernobyl "exclusion zone," a Russian security source said.
Russia wants to take control of the Chernobyl nuclear reactor to signal NATO that it will not interfere militarily, the source added.
In 1986, the Chernobyl disaster in then-Soviet Ukraine had sent clouds of nuclear material over Europe. This occurred because of a botched safety test at the nuclear plant's fourth reactor.
Now it has become a tourist attraction. The Chernobyl area was closed to tourists a week before the Russian conflict with Ukraine broke out.
In a tweet, Ukrainian President Volodymyr Zelenskiy said, "Our defenders are giving their lives so that the 1986 tragedy will not be repeated. This is a declaration of war to all of Europe."