It may include lethal and non-lethal weapons and methods depending upon the restrictions imposed by civilian law, military rules of engagement, or ethical codes. Close combat using firearms or other distance weapons by military combatants at the tactical level is modernly referred to as close quarter battle. The United States Army uses the term combatives to describe various military fighting systems used in hand-to-hand combat training, systems which may incorporate eclectic techniques from several different martial arts and combat sports.