Negotiators from Russia and Ukraine met on Monday for another round of talks aimed at finding a way out of the war even as Russian forces broadened their devastating offensive and the Kremlin insisted that it would not pull back until “all plans” for the invasion were fulfilled.

Mykhailo Podolyak, a member of Ukraine’s delegation, said on Monday afternoon that the talks had taken a “technical pause” and would resume on Tuesday.

Before the talks, which were held virtually, Ukrainian officials hinted at progress, with one member of Kyiv’s delegation saying over the weekend that Russia was “much more sensitive to Ukraine’s position” and that “some concrete results” could be reached within days.

But several rounds of meetings have failed to make progress towards a ceasefire. In recent days Russia has intensified its attacks, launching a flurry of strikes in Kyiv on Monday, a day after targeting a military base less than 20km from Poland, a country where Nato troops are deployed at the border.

Western officials cautioned that the strike could represent a shift of tactics in a war that many were already worried could metastasise into a larger European conflict.

A pregnant woman who was photographed in the aftermath of a Russian strike against a maternity hospital in Mariupol has died, along with her baby.

Their deaths were reported by the Associated Press, one of the few news organisations still able to report from the city.