The Group of Seven industrialised nations has condemned Russia's occupation of the Zaporizhzhia nuclear power plant and called on Moscow to immediately hand back full control of the plant to Ukraine.

Ukrainian staff operating the plant "must be able to carry out their duties without threats or pressure," said the G7 foreign ministers in a statement. "It is Russia's continued control of the plant that endangers the region."

Zaporizhzhia, the biggest nuclear power plant in Europe, is in southern Ukraine.

Moscow and Kyiv blame each other for the latest strike at the Zaporizhzhia plant, Europe's largest nuclear power site, which has been under Russian control since the early days of the war.

The fighting last Friday at the plant prompted the UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), to warn of "the very real risk of a nuclear disaster".

Head of Ukraine's state nuclear power firm Energoatom Petro Kotin also said that it is vital for the Ukrainian government to regain control of the plant in time for winter.

Earlier this week, United Nations Secretary-General Antonio Guterres warned that any attack on a nuclear plant is "suicidal".

"Any attack to a nuclear plant is a suicidal thing. I hope that those attacks will end, and at the same time I hope that the IAEA will be able to access the plant," Mr Guterres said on Monday.

And Mr Kotin revealed that Russian shelling last week damaged three lines that connect the plant to the Ukrainian grid, and accused Russia of trying to connect the facility to its own grid.

He warned that "the risk is very high" of shelling hitting containers storing radioactive material.

Both Ukraine and Russia have said they want technicians from the UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), to visit Zaporizhzhia.

Russia has asked for IAEA chief Rafael Grossi to brief the UN Security Council on Moscow's accusation of attacks by "the Ukrainian armed forces on the Zaporizhzhia nuclear power plant and their potential catastrophic consequences," diplomats said.

Meanwhile, Russia has "almost certainly" established a major new ground forces formation to support its operations in Ukraine, British military intelligence has said.