The U.N. Secretary General, the Presidents of Turkey and Ukraine, and nuclear experts around the world are all saying a nuclear disaster is imminent. The concern centers around the Zaporizhzhia nuclear power plant, the largest nuclear power plant in Europe.

Russia captured the plant in southern Ukraine soon after it invaded back in February and has been using the plant as cover to launch attacks on neighboring communities.

On Thursday, though, Russia told the majority of workers at the plant to stay home on Friday. Russian state-owned media even reported the U.S. and Ukraine were planning to shell the facility, and preemptively blamed the West for the nuclear fallout that would happen if the plant were attacked. Meanwhile, critics of the Kremlin warned of potential sabotage by the Russians.

New video circulating online also shows several Russian military vehicles inside the plant and near one of the reactors. There are only two active reactors at the site. The other four have been taken offline.

Residents near the plant said they’ve seen Russians firing rockets from the nuclear site.

Ukraine military intelligence told NBC News this all could be evidence of a planned, large-scale provocation by the Russians.

Residents in Ukraine have been practicing nuclear disaster response drills as threats of a potential nuclear incident grow.

The international community is calling for Russia’s immediate withdrawal from the nuclear power plant and a demilitarization of the area.

Russia is rejecting that idea and instead may disconnect the plant from the grid. When it was fully operational, the plant provided 20% of Ukraine’s electricity.

Ukrainian leaders warned Friday the probability of a major act of terror at the facility is very high.