Ukrainian President Volodymyr Zelenskiy has denied a claim by Russia’s defense ministry that Russian forces captured Kostiantynivka, a city in eastern Ukraine.

Russia announced the alleged capture as part of its broader efforts to advance in the region. Ukraine, however, said the Russian claim was not accurate.

The back-and-forth underscores the fluid and contested nature of the front line in eastern Ukraine, where both sides frequently dispute battlefield developments and the status of towns and positions.