On April 22, 1992, he was approved as the Minister of Defense of Belarus. During his tenure, he distinguished himself by firing officers from the army who were members of the Belarusian Military Association. Many consider him to be the founder of the modern Belarusian army, which previously inherited Soviet era technologies and traditions. On 8 September 1992, he presided over the first oath taking ceremony that held on Independence Square, held on the 478th anniversary of the Lithuanian-Polish victory at the Battle of Orsha, which was established as a Day of Belarusian Military Glory. Under his control, disarmament of the army, causing Belarus to become the first nuclear-free state in the post-Soviet space. At the end of July 1994, after Alexander Lukashenko came to power, Kozlovsky resigned along with the entire government of Vyacheslav Kebich. On September 5 of the same year, by presidential decree, he was demoted to lieutenant general for abuse of office (which was not established by the investigation).