Ukraine has become a dark patch on the globe at night, images released by US space agency Nasa show, as repeated Russian missile strikes cripple the country’s energy network.
The images, taken from space, show Ukraine in total darkness, surrounded by bright spots coming from other countries.
Since October, Russia has launched regular strikes with the aim of destroying the Ukrainian power grid.
Ukraine's President Volodymyr Zelenskyy told the Financial Times that this week's strikes had created a situation not seen for 80 or 90 years ― "a country on the European continent where there was totally no light."
"The situation with electricity remains difficult in almost all regions," he said in his nightly address on Thursday.
"However, we are gradually moving away from blackouts - every hour we return power to new consumers."
More than 24 hours after Russian strikes smashed Kyiv, mayor Vitali Klitschko said late on Thursday that 60 per cent of homes in the capital were still suffering emergency outages, amid temperatures well below freezing.
Water services had been fully restored however, said city officials.
"We understand that missile strikes like this could happen again. We have to be ready for any developments," said Mr Klitschko according to Kyiv city council.
Ukrenergo, which oversees Ukraine's national power grid, said 50 per cent of demand was not being met as of 7pm Kyiv time on Thursday.
Authorities have set up "invincibility centres", where people can charge phones, warm up and get hot drinks.
"It is the second day we are without power and food. More than 60 children are waiting for food and we cannot prepare anything unless the power gets fixed," said a woman at one such centre in Kyiv.
British Foreign Minister James Cleverly travelled to Ukraine on Thursday to pledge the UK’s support for as long as it takes to defeat Russia and pledge millions of pounds in further support to ensure the country has the help it needs through winter, his office said on Friday.
Mr Cleverly, who is set to meet Mr Zelenskyy on the trip, condemned Russia for its "brutal attacks" on civilians, hospitals and energy infrastructure.
He said: “As winter sets in, Russia is continuing to try and break Ukrainian resolve through its brutal attacks on civilians, hospitals and energy infrastructure. Russia will fail.
“Our support will continue for as long as it takes for this remarkable country to recover.”
The war's first winter will now test whether Ukraine can press on with its campaign to recapture territory, or Russia's commanders can halt Kyiv's momentum.
Mr Zelenskyy said in some areas Ukrainian troops were preparing to advance but gave no details.
Having retreated, Russia has a far shorter line to defend, to hold on to seized lands, with more than a third of the front now blocked off by the Dnipro River.
Russia has pursued an offensive of its own along the front line west of the city of Donetsk, held by its proxies since 2014.
Ukraine said Russian forces tried again to advance on their main targets, Bakhmut and Avdiivka, with limited success.
Agencies in the area could not immediately verify the battlefield accounts.
British military intelligence said Russia continued to struggle in its partial mobilisation, with an increasing number of reservists prepared to face arrest rather than fight in Ukraine.
“Their deployment is often characterised by confusion over eligibility for service, inadequate training and personal equipment, and commitment to highly attritional combat missions,” the UK Ministry of Defence said in its daily intelligence update shared on Twitter.
Many are being compelled to serve with serious and chronic health conditions, it said.
“Mobilised reservists have highly likely experienced particularly heavy casualties after being committed to dig ambitious trench systems while under artillery fire around the Luhansk Oblast town of Svatove,” said the ministry.
“In Donetsk Oblast, reservists have been killed in large numbers in frontal assaults into well-established Ukrainian defensive zones around the town of Bakhmut.
“The Kremlin will likely be concerned that an increasing number of reservists’ families are prepared to risk arrest by protesting against the conditions their relatives are serving under.”
