Russia has intensified its offensive in eastern Ukraine as US-led peace efforts falter, with some of Moscow’s forces entering the stronghold of Pokrovsk.

Kyiv has denied Russian claims that its troops were completely surrounded in the eastern Ukrainian city, which served as a logistical hub until last year and, if captured, could be used as a staging ground for deeper Russian advances. But Ukraine’s general staff on Sunday acknowledged that some 200 Russian troops had entered Pokrovsk and that fierce fighting was under way at multiple flashpoints along the 1,000km-long frontline.

Ukrainian President Volodymyr Zelenskyy said reports of encirclement were “a complete lie” after Russia’s chief of general staff Valery Gerasimov on Sunday claimed some 5,500 Ukrainian troops near Pokrovsk were completely surrounded, without providing any evidence.