Russia's full-scale war against Ukraine is in a "new phase," President Volodymyr Zelensky said in an interview with the Associated Press published on Dec. 1. “We have a new phase of war, and that is a fact...winter as a whole is a new phase of war,” he said. When asked about the counteroffensive, he acknowledged it had not gone as Ukraine had hoped, admitting that it "did not achieve the desired results."
They are literaly the ones who named it that.