A surprise Ukrainian offensive in a western region of Russia came to the end of a fourth day.

Ukrainian troops remained in Russia’s western Kursk region on Friday night, as its surprise cross-border offensive into Russia came to the end of a fourth day.

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Reports suggest that Ukrainian troops are operating more than 10km (six miles) inside Russia - the deepest cross-border advance by Kyiv since Moscow launched its full-scale invasion of Ukraine in February 2022.