Russian and Ukraine traded blame Thursday as Europe’s largest nuclear power plant, currently held by Russian troops, was again subjected to shelling ahead of an emergency meeting of the United Nations security council called to air global concerns over the complex.

Each side said there were 10 hits on the plant’s administrative office and fire station.

UN Secretary-General António Guterres expressed his “grave” concern over the continued fighting in the area and called on both sides to cease all military activity around the plant and “exercise common sense and reason” to avoid “catastrophic consequences.”

Ukrainian forces “once again struck the Zaporizhzhia nuclear power plant,” Vladimir Rogov, a member of the Moscow-installed regional administration, said on the Telegram messaging app.

He alleged that Ukraine was trying to strike at concrete storage facilities at the nuclear power plant, where thousands of tons of radioactive waste are stored.

Ukraine’s interior minister, Denys Monastyrsky, said that Ukraine had to be ready for any scenario at the Russian-controlled plant, including evacuating people from the area.

“The plant is as of today not only in the hands of the enemy, but in the hands of uneducated specialists who could potentially allow for a tragedy to happen,” Monastyrsky told Reuters in an interview.

“Of course, it’s difficult to even imagine the scale of the tragedy which could come into effect if Russians continue their actions there,” he said, adding that Ukrainian state emergency services were outlining various responses, “including the question of evacuations.”

Ukrainian nuclear agency Energoatom said in a statement that “the Russians shelled the Zaporizhzhia nuclear power plant again.”

Neither side reported casualties.

The latest reported strike comes a day after Ukraine accused Russia of carrying out rocket strikes that killed 14 civilians in areas near the nuclear power plant.

Kyiv has argued that Moscow has turned the nuclear plant into a military base, firing missile strikes from the vulnerable position while knowing Ukraine will be hesitant to fire back in the direction of the nuclear plant.

“Russia has become a terrorist state, and is actually holding nuclear plants hostage, and is blackmailing everyone with a probable disaster,” Ukrainian President Volodymyr Zelensky told a briefing Thursday. “None of us can stop the wind if it carries radiation.”

The UN has called on both sides to immediately grant the International Atomic Energy Agency access to the Zaporizhzhia nuclear power plant.