Shortly before the one-year anniversary of the full-scale invasion of Ukraine on Friday, Kiev said that the Russian army was reinforcing its various front line positions.
The General Staff of the Ukrainian Armed Forces said this suggested that new attacks were imminent.
The Russian forces focused their main reinforcement efforts "on offensive operations in the directions of Kupiansk, Lyman, Bakhmut, Avdiivka and Shakhtarsk," the Ukrainian military command's statement on Wednesday evening said.
Heavy fighting continues around Bakhmut in particular, it said, adding that with the help of its aerial reconnaissance, the Russian military is trying to coordinate the artillery attacks more precisely.
Russian attacks were repelled near Avdiivka and Shakhtarsk, the General Staff said.
