Ukraine said an explosion rocked Kyiv on Wednesday night near the city’s central train station where thousands of people are being evacuated.

       There was no immediate word on casualties and the station building suffered minor damage, an official said. Trains continued to run.

       But the blast may have cut off central heating supply to parts of the Ukrainian capital amid freezing winter temperatures, Interior Ministry adviser Anton Herashchenko said in an online post.

       Mr Hershchenko said it was caused by falling wreckage from a Russian missile that was downed by Ukrainian air defence.

       The falling debris hit a heating pipe and caused it to explode but resulted in far less damage and casualties than if the missile had hit its target in central Kyiv, he said, without saying if anyone had been hurt in the explosion.

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       The incident took place between the Southern Railway station and the Ibis hotel, an area near Ukraine’s Defense Ministry.

       A US official said Russian forces appeared to be getting more aggressive in targeting infrastructure inside Kyiv as its advances slow in the face of Ukrainian resistance.

       A woman cries in the cellar of a house crowded with people sheltering from Russian airstrikes, outside Kyiv

       (AP)

       Ukraine’s second biggest city, Kharkiv, also suffered heavy bombardment on the seventh day of the war but Ukrainians denied Russia’s claim that its forces had taken the Black Sea port of Kherson.

       A US official said control of Kherson remained contested.

       Russian forces continued their assault on the southeastern port city of Mariupol. The city’s Mayor Vadym Boychenko said the attacks there had been relentless. At least one teenager died and two more were wounded by apparent Russian shelling.

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       In the northern city of Chernihiv, two cruise missiles hit a hospital, according to the Ukrainian UNIAN news agency.

       The United Nations General Assembly voted overwhelmingly to deplore the Russian invasion “in the strongest terms” and demand that Moscow withdraw its forces.

       Additional reporting by agencies