Ukraine is heading into what a senior United Nations official has called its most dangerous winter since Russia launched its full-scale invasion more than four and a half years ago, as relentless Russian strikes continue to batter the country's energy infrastructure, cities, and civilian sites. Alexander De Croo, a former prime minister of Belgium now serving as a UN Development Programme official, told the BBC that Ukraine was entering the season "from a very weak base" and that the UN was "very, very worried about what this winter could become."

The warning comes amid a sustained and widening Russian air campaign. In recent days alone, at least nine people were killed in overnight strikes, including two workers at an ArcelorMittal steel plant in Kryvyi Rih, a major industrial city in central Ukraine. The company condemned the attack on what it described as a "civilian installation of the mining and metallurgical industry." Further strikes killed two people in a residential building in Zaporizhzhia, a southern Ukrainian city, and three civilians were killed by drone strikes targeting civilian vehicles in Kramatorsk, in the east. Attacks also struck a residential building in Odessa and a hotel in the nearby port town of Chornomorsk. Ukrainian President Volodymyr Zelensky said strikes hit ten regions in a single night, describing the assault as "absolute terror."

Earlier in the week, Russian strikes hit shopping malls in Pavlohrad, Zaporizhzhia, and Sumy, killing seven people in total and wounding nearly a hundred. Russia has also begun deploying faster, jet-powered drones that are significantly harder to intercept, particularly over Kyiv. Both sides deny deliberately targeting civilians. Ukraine has continued its own long-range strikes deep into Russian territory, hitting oil facilities, refineries, and logistics warehouses, including a drone attack on the Black Sea resort city of Sochi that wounded 28 people.

The humanitarian stakes heading into winter are severe. Temperatures in Ukraine regularly fall to -20°C, and De Croo warned that if energy infrastructure is critically damaged, water and sewage systems could fail — pushing the country toward what he called "circumstances which would be really close to humanitarian catastrophe." UN teams are working to rebuild damaged energy systems and establish decentralised power plants less vulnerable to attack, but De Croo acknowledged it was "almost an impossible task," with repair crews forced to halt work repeatedly due to ongoing air raid alarms at sites that are themselves targets.

Diplomatic efforts to end the conflict, mediated by the United States, have so far produced no concrete results. Zelensky has called on US President Donald Trump to impose "severe" sanctions on Russia immediately to limit its ability to produce missiles. The violence has resumed and escalated despite envoys from the Trump administration having visited both Moscow and Kyiv the previous weekend for talks with President Putin and President Zelensky respectively.