The Group of Seven of the world’s advanced economies condemned Russia’s kidnapping of the leadership of Ukraine’s Zaporizhzhia nuclear power plant and called for the immediate return of full control of the facility to Kyiv.

“We condemn Russia’s repeated kidnapping of Ukrainian” Zaporizhzhia nuclear plant “leadership and staff and denounce the application of other forms of pressure on remaining Ukrainian personnel,” the Nonproliferation Directors General of the G7 countries wrote in a statement Saturday evening. The group includes the U.S., Canada, France, Germany, Italy, Japan and the U.K.

They urged Russia “to immediately return full control” of the plant “to its rightful sovereign owner, Ukraine, to remove all Russian personnel from the facility, and to stop any attempts to recklessly and dangerously place” it under Russian administration “which could further jeopardize its safe and secure operations.”

Russian President Vladimir Putin this month ordered his government to take control of the Zaporizhzhia plant, Europe’s largest nuclear power facility.

The alarm over the nuclear plant comes as Ukraine’s air force said in a statement on Saturday that Russia launched a “massive missile attack” pounding energy facilities and other infrastructure in central and western parts of Ukraine, leaving hundreds of thousands of people without power. Parts of Kyiv suffered power cuts into the evening.

“The geography of this latest mass strike is very wide,” Ukrainian President Volodymyr Zelenskyy said in his nightly video address. And on Sunday, according to the Agence France-Presse, Kyiv’s energy operator said that scheduled “stabilization” power cuts have been introduced in the Ukrainian capital after the repeated Russian strikes.

Energoatom, Ukraine’s state nuclear energy agency, on Tuesday accused Russia of detaining two senior employees at the Russian-controlled Zaporizhzhia nuclear power plant in southern Ukraine, according to media reports.

In a statement on social media, Energoatom said Russian forces on Monday “kidnapped” the head of information technology Oleg Kostyukov and the plant’s assistant general director Oleg Osheka and “took them to an unknown destination.”

In a separate development of the war, that has now reached its eight month, Ukraine’s air force reported on Sunday that 14 Iranian-made “Shahed-136” kamikaze drones were shot down overnight in Mykolaiv Oblast, in southern Ukraine.

The EU this week sanctioned three top Iranian generals and the Iranian drone maker Shahed Aviation Industries, and also proposed to further sanction two individuals and two entities already hit by restrictive measures, “in view of their role in the development and delivery” of the drones to Russia.

Tehran denies supplying drones to Moscow in the Ukraine war and on Saturday reportedly strongly condemned a call by France, Germany and the U.K. for the United Nations to investigate the accusations that Russia has used Iranian-made drones.