Yes. Police and other administrative checks are always possible, including within the territory and at internal borders for security and migration purposes. It is important to cooperate and provide the required documents and information to police or border guards. In certain circumstances you may be required to remain available to the authorities during these checks in designated facilities.
Source: https://ec.europa.eu/info/strategy/priorities-2019-2024/stronger-europe-world/eu-solidarity-ukraine/eu-assistance-ukraine/information-people-fleeing-war-ukraine_en