KYIV — A prominent Ukrainian officer this week accused a top commander of incompetence, blaming him for “thousands” of casualties in a rare public criticism from within the military that reflects growing discontent among the troops as Russia has advanced on the battlefield.

       Maj. Bohdan Krotevych, the chief of staff of the influential Azov Brigade, filed a request to Ukraine’s State Bureau of Investigation concerning “a military general who in my opinion has killed more Ukrainian soldiers than any Russian general,” he wrote Monday in a post on Telegram.