Diplomatic efforts to end the war in Ukraine stepped up on Monday, with Ukrainian and Russian negotiators set to talk again after both sides cited progress, even after Russia attacked a base near the Polish border and fighting raged elsewhere.

A barrage of Russian missiles hit Ukraine's Yavoriv International Centre for Peacekeeping and Security, a base just 25km from the Polish border that has previously hosted Nato military instructors, killing 35 people and wounding 134, a Ukrainian official said yesterday.

Russia's defence ministry said...