Missiles struck near Ukraine’s southern port of Odesa on Sunday with Russia saying it had destroyed an oil refinery used by the Ukrainian military, while attempts to evacuate people from the devastated city of Mariupol were due to continue.

There was little sign of a breakthrough in efforts to negotiate an end to the five-week war, although Russia’s chief negotiator said talks were due to resume on Monday.

In Odesa, the city council said “critical infrastructure facilities” were hit by missiles. No casualties were reported.

Russia’s defence ministry said strikes by its military destroyed an oil refinery and three fuel storage facilities near Odesa. It said the facilities were used to supply Ukrainian troops near the city of Mykolaiv.

Odesa, on the Black Sea, is the main base for Ukraine’s navy. It has been targeted by Russian forces seeking a land corridor to Transdniestria, a Russian-speaking breakaway province of Moldova which hosts Russian troops.