Ukrainian president Volodymyr Zelensky has told Europeans to expect a difficult winter as the Russian assault on his country leads to cuts in oil and gas exports by Moscow.
Mr Zelensky warned in his daily video address that Russia is preparing for a “decisive energy blow on all Europeans for this winter”.
He was speaking on Saturday after Moscow shut down a main pipeline that supplies Russian gas to the continent.
Moscow has cited Western sanctions imposed over its invasion of Ukraine and technical issues for the energy disruptions.
European countries which have backed the Kyiv government with diplomatic and military support have accused Russia of weaponising energy supplies.
Some analysts say the shortages and a surge in living costs as winter approaches risk sapping Western support for Kyiv as governments try to deal with disgruntled populations.
Last week Moscow said it would keep the Nord Stream 1 pipeline, its main gas channel to Germany, closed and G7 countries announced a planned price cap on Russian oil exports.
In response, the Kremlin said it would stop selling oil to any countries that implemented the cap.
German chancellor Olaf Scholz said on Sunday that his government had been planning for a total halt in gas deliveries in December but he promised that his country would make it through the winter.
“Russia is no longer a reliable energy partner,” Mr Scholz told a news conference in Berlin.
Meanwhile, UN inspectors said on Saturday that the Russian-occupied Zaporizhzhia nuclear plant in southern Ukraine again lost external power.
The last remaining main external power line was cut off although a reserve line continued supplying electricity to the grid, the International Atomic Energy Agency (IAEA) said in a statement.
Only one of its six reactors remained in operation, it said.
The plant was seized by Russian troops shortly after president Vladimir Putin sent his army over the border on 24 February earlier this year and has become a focal point of the conflict.
Each side has blamed the other for shelling in the vicinity that has raised fears that a nuclear disaster could be triggered.
An official from the Russian-installed administration in Zaporizhzhia said the situation around the plant had been calm so far on Sunday.
Speaking to Komsomolskaya Pravda radio, the official, Vladimir Rogov, said there had been no shelling or incursions. Russia has twice accused Ukraine of trying to capture the plant in the past two days. Ukraine said Russia had attacked the area itself.
IAEA experts are expected to continue working at the plant until at least Monday, Mr Rogov was quoted as saying.
An IAEA mission toured the plant, which is still operated by Ukrainian staff, last week and some experts have remained there pending the release of an IAEA report.
The plant said in a statement on Saturday the fifth reactor was switched off “as a result of constant shelling by Russian occupation forces” and that there was “insufficient capacity from the last reserve line to operate two reactors”.
Mr Zelensky has blamed Russian shelling for a cut-off on 25 August. The first Zaporizhzhia was severed from the national grid, which narrowly avoided a radiation leak. That shutdown prompted power cuts across Ukraine.