Militarization of police refers to the use of military equipment and tactics by law enforcement officers. This includes the use of armored personnel carriers, assault rifles, submachine guns, flashbang grenades,grenade launchers,sniper rifles, and Special Weapons and Tactics (SWAT) teams. The militarization of law enforcement is also associated with intelligence agency-style information gathering aimed at the public and political activists, and a more aggressive style of law enforcement. Criminal justice professor Peter Kraska has defined militarization of police as "the process whereby civilian police increasingly draw from, and pattern themselves around, the tenets of militarism and the military model."
Observers have noted the militarizing of the policing of protests. Since the 1970s, riot police have fired at protesters using guns with rubber bullets or plastic bullets.Tear gas, which was developed for riot control in 1919, is widely used against protesters in the 2000s. The use of tear gas in warfare is prohibited by various international treaties that most states have signed; however, its law enforcement or military use for domestic or non-combat situations is permitted.