Russian forces are continuing their attacks on Ukraine's energy infrastructure, forcing millions of people to go without electricity in the capital Kyiv and elsewhere.

Ukrainian President Volodymyr Zelenskyy said on Sunday that electricity is being restricted in Kyiv and other regions due to power shortages. He said as of Sunday evening more than 4.5 million people were without electricity.

He noted Russia is concentrating forces and the means for a possible repetition of a mass attack on the country's infrastructure. He stressed Ukrainians must endure the winter and be stronger and prepare for the liberation of their territory.

Russia's state-run Tass news agency reported on Sunday that electricity had been cut off to more than 10 settlements in the Kherson region, including the city of Kherson. Ukrainian forces are continuing their offensive to retake territories captured by Russia in the southern area.

Pro-Russian authorities in Kherson say the blackouts are the result of acts of sabotage by Ukraine. They say the city's water supply has been interrupted.

Russian troops are showing signs of withdrawing from areas near Kherson. But the Ukrainian military is wary of Russia's information operation, saying Moscow may be preparing for urban combat in the city.

On Thursday, the commander-in-chief of Ukraine's armed forces, General Valerii Zaluzhnyi, said Russia has lost 278 aircraft since the start of the invasion. He said that is more than twice the number of aircraft the Soviet Union lost during the war in Afghanistan.

The British Defence Ministry said in its intelligence update on Monday that "Russia's continued lack of air superiority is likely exacerbated by poor training, loss of experienced crews, and heightened risks of conducting close air support in dense air defence zones."

It said Russia's aircraft losses are expected to outstrip their capacity to manufacture new airframes and the situation is unlikely to change in the next few months.