Russia’s attacks on Ukraine’s power grid show Vladimir Putin plans to use “winter as a weapon of war”, NATO’s secretary-general Jens Stoltenberg has warned.

Mr Stoltenberg said Mr Putin was using frost, snow and ice to his advantage on the battlefield as millions of Ukrainians face a freezing winter without reliable electricity.

NATO will step up its support for Ukraine amid such a “horrific” development that shows no sign of ending, he said.

“President Putin is now trying to use the winter as a weapon of war against Ukraine,” Mr Stoltenberg said ahead of a NATO foreign ministers’ meeting in Bucharest, Romania.

“This is horrific and we need to be prepared for more attacks.”

Snow falls on buildings destroyed by Russia. Photo: Getty

In Kyiv, snow is falling and temperatures hovering around freezing as millions struggle with disruptions to electricity supply and central heating caused by the waves of Russian air strikes.

Earlier Ukraine had accused the Kremlin of reviving the “genocidal” tactics of Josef Stalin’s Soviet-era famine that killed millions of Ukrainians in the winter of 1932-33.

Ukrainian President Volodymyr Zelensky cautioned that Russia was “planning new strikes” that could bring a new week of strain on the power grid.

“We understand that the terrorists are planning new strikes. We know this for a fact,” Mr Zelensky said.

“And as long as they have missiles, they, unfortunately, will not calm down.”

The coming week could be as difficult as the previous one, he added.

There was no response from Moscow to Mr Zelensky’s claims.

City authorities said workers were close to completing restoration of power, water and heat, but high consumption levels meant some blackouts had been imposed.

The Kremlin last week denied its attacks on Ukraine’s electricity network were aimed at civilians, but said Kyiv could “end the suffering” of its population by meeting Russia’s demands to resolve the conflict.

Russian attacks have increased in recent weeks, with repair workers racing to fix wrecked power facilities as the cold weather boosts energy demand.

Mr Zelensky said utility and emergency teams were working around the clock to provide power, with the situation “under control” though most regions were subject to scheduled blackouts to help restore the grid.

In Kherson, a city in southern Ukraine abandoned by Russian troops this month, regional governor Yaroslav Yanushevych said 17 per cent of customers now had power. Other districts would be connected in coming days.

Separately, the Pentagon is considering a Boeing proposal to supply Ukraine with cheap, small precision bombs fitted onto abundantly available rockets, allowing Kyiv to strike far behind Russian lines.

Boeing’s proposed system, dubbed Ground-Launched Small Diameter Bomb, is one of about a half-dozen plans for getting new munitions into production for Ukraine and America’s Eastern European allies, industry sources said.