WASHINGTON (NewsNation Now) — Russian forces have seized control of the Chernobyl power plant in Ukraine, the site of one of the world’s worst nuclear disasters, and are reportedly holding staff hostage, according to Ukrainian officials.

Russia’s capture raises concerns for a secondary catastrophe due to the fighting between the ex-Soviet neighbors: another nuclear reaction at the Chernobyl site 35 years later.

“This unlawful and dangerous hostage-taking, which could upend the routine civil service efforts required to maintain and protect the nuclear waste facilities,” said White House press secretary Jen Psaki.

On Thursday, Russian troops took over the power plant while Ukrainian forces battled them on three sides after Moscow mounted an assault by land, sea and air in the biggest attack on a European state since World War II. 

“Our defenders are giving their lives so that the tragedy of 1986 will not be repeated,” Ukrainian President Volodymyr Zelenskyy tweeted shortly before the power plant was captured. “This is a declaration of war against the whole of Europe.”

Mykhailo Podolyak, an adviser to Zelenskyy, called the Russian takeover “one of the most serious threats to Europe today.”

“It is impossible to say that Chernobyl is safe,” he added.

Oksana Makarova, Ukrainian ambassador to the U.S., said Ukrainian forces put up an intense fight trying to defend Chernobyl, and now that the site is under Russian control Ukrainian troops won’t give up on fighting to take it back.

“The combat spirit of the Ukrainian military is high. We are fighting, we will be fighting,” Makarova said. “We are protecting our home and we will not stop.”

Yet, despite the hopeful tone, at the moment, the assessment is bleak. Not only dangerous, but a strategic location about 60 miles from Kyiv, Chernobyl could serve Russian troops as a base or rallying point to launch an attack on the capital city.

Russia said Friday it was working with the Ukrainians to secure the plant. There was no corroboration of such cooperation from the Ukrainian side.

Meanwhile, Ukraine’s nuclear energy regulatory agency said on Friday it was recording increased radiation levels in the area near the decommissioned Chernobyl nuclear power plant.

The State Nuclear Regulatory Inspectorate said that higher gamma radiation levels have been detected in the Chernobyl zone, but didn’t provide details of the increase.

It attributed the rise to a “disturbance of the topsoil due to the movement of a large amount of heavy military equipment through the exclusion zone and the release of contaminated radioactive dust into the air.”

Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said Russian airborne troops were protecting the plant to prevent any possible “provocations.” He insisted that radiation levels in the area have remained normal.

The Vienna-based International Atomic Energy Agency said it was told by Ukraine of the takeover, adding that there had been “no casualties or destruction at the industrial site.”

The Chernobyl disaster occurred in then-Soviet Ukraine when a nuclear reactor at the plant 80 miles north of Kyiv sent clouds of nuclear material across much of Europe in 1986 after a botched safety test in the fourth reactor of the atomic plant. The damaged reactor was later covered by a protective shell to prevent leaks.

Decades later, the still-radioactive site became a tourist attraction. About a week before the Russian invasion, the Chernobyl zone was shut down for tourists.

Ukraine’s neighbor, Poland, said it had not recorded any increase in radiation levels on its territory.

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