Russian drones have pummeled the Ukrainian Black Sea port city of Odesa, injuring three people, sparking fires, and underlining challenges for even a limited truce.

Russia pounded Ukraine's Black Sea city of Odesa late on Thursday with one of its biggest drone attacks, injuring three teenagers and sparking fires as the Czech president visited, Ukrainian officials said.

The attack underlined Moscow’s intention to pursue aerial attacks even as it agreed to temporarily halt strikes on energy facilities.