Russian President Vladimir Putin has called on Ukrainian troops in the Russian region of Kursk to surrender, as diplomatic back-and-forth continues over a potential US-brokered ceasefire with Ukraine.

Russia’s president, Vladimir V. Putin, dressed in fatigues, visited a command post near the front in Kursk late Wednesday to cheer on his military’s ejection of Ukrainian forces from much of the territory they had been occupying in the Russian border region.