Deadly force, also known as lethal force, is the use of force that is likely to cause serious bodily injury or death to another person. In most jurisdictions, the use of deadly force is justified only under conditions of extreme necessity as a last resort, when all lesser means have failed or cannot reasonably be employed.
Warning sign at Langley Air Force Base
Deputy Sheriff with Reising submachine gun.
The use of force, in the context of law enforcement, may be defined as the "amount of effort required by police to compel compliance by an unwilling subject".
A St. Paul police SRT indexing a firearm in a gun holster
A baton used by riot police
Japan Coast Guard officer firing handgun