Ukraine’s state-owned grid operator Ukrenergo this week dismissed as “physically impossible” the suggestion by a Russian official that Ukraine’s besieged Zaporizhzhya nuclear power plant would supply Russia with electricity.

Russian troops in March seized the Zaporizhzhya plant, the biggest in Europe, and have since held the Ukrainian staff onsite to continue running it. The RIA news agency had earlier quoted Russian Deputy Prime Minister Marat Khusnullin as saying the facility would provide energy to Russia and to Ukraine – so long as Ukraine paid Russia for it.

“If Ukraine’s power system will be ready to pay, then we’ll work; if it won’t, the plant will work for Russia,” Khusnullin said in remarks to the Russia state-run news service.

Ukrenergo quickly retorted on its Telegram channel, saying the country’s power grid has no physical connections with Russia, and emphasizing that the plant remained in control of Ukrainian specialists.

“Ukraine’s power system currently has no physical connections with Russia’s power system. Therefore, the supply of electricity from Ukrainian power plants to Russia is currently physically impossible,” Ukrenergo said in its statement.

“Any change in the situation at ZNPP will mean an act of nuclear terrorism,” the agency added.

Ukraine’s Energoatom, which operates all four of Ukraine’s nuclear power plants,  said in a statement the same day that: “there’s no technical or any other possibility” for siphoning off the plant’s electricity to Russia, adding that both the plant and the city of Enerhodar where it is located in “will soon be returned to Ukraine.”

The Zaporizhzhya plant has been in Russian hands since March 4, when troops shelled the plant in a dramatic attack that raised the specter of a Chernobyl-like nuclear disaster.

Located in the Zaporizhzhya Oblast in southeastern Ukraine, the plant has fallen into Russia’s crosshairs as Moscow’s troops look to establish control of the neighboring Donbas region.

Since the takeover, Ukrainian staff have been held at gunpoint and are made to answer to officials from Rosatom, Russia’s state nuclear corporation – a situation the International Atomic Energy Agency has called “fragile” and “unsustainable.”

Rafael Grossi, the agency’s head, has implored both the Ukrainian and Russian sides to allow agency monitors to launch a safety mission the plant, so far with no success, as each side levies its own demands on IAEA inspectors.

Russian forces also held, then later withdrew from, Chernobyl, site of the world’s worst nuclear accident in 1986. An influx of heavy armored vehicles at the site churned up plumes of radioactive dust and fighting in the area knocked out electricity to spent nuclear fuel cooling at the site twice, though it was restored on each occasion.