Ukrainian leaders saw troops cross their border almost a year ago and fear the Russians "want to do something symbolic" around the anniversary of the invasion. They say their enemies have suffered a string of defeats and may want "revenge."

Russian fighters have tried month after month to capture the city of Bakhmut in the Donetsk region. But they have struggled to break through.

Ukrainian President Volodymyr Zelenskyy said, "We are paying particular attention to Bakhmut, to our defenses, and to the occupier's attempts to surround the city. And we are countering them."

The head of the Wagner mercenary group said Ukrainian forces are defending "every street, every house, every stairwell." On Monday, Yevgeny Prigozhin issued a challenge to Zelensky. He said, "We have just landed after bombing Bakhmut. Tomorrow I am boarding a MiG-29. If you want, let's meet in the sky."

Ukrainian troops with the Azov battalion say their enemies have learned how to adapt. But they say the Russians will not succeed and will become "fertilizer" for Ukrainian soil.

British intelligence analysts say, in September, pro-Russian authorities will hold elections in occupied areas of Ukraine. The votes will coincide with regional votes across Russia. Those authorities held referendums last September in four regions, then annexed the areas illegally.