A police tactical unit (PTU) is a specialized police unit formed and trained to handle situations that are beyond the capabilities of ordinary law enforcement forces because of the level of violence - or risk of violence - involved. Their missions include serving of search warrants for dangerous persons, arresting or neutralizing dangerous or deranged armed persons and intervening in high risk situations such as shootouts, hostage taking and terrorist incidents.[Note 1]
Police tactical units are permanent units composed of personnel carefully selected who are regularly trained in the legal, tactical and psychological aspects of their missions. They are equipped with specialized police and military-type hardware.
They are usually part of either :
but, depending on the country, other administrations - such as the coast guard, customs or penitentiary services for example - sometimes setup specialized units with comparable missions, training and equipment.
In the United States, police tactical units are often known as Special Weapons And Tactics (SWAT) teams; the term originally referred to the Los Angeles Police Department's PTU but is now commonly used in the U.S. as a catchall genericized trademark to refer to any such unit. In Australia, police tactical units are formally known as a police tactical group. The European Union uses the term Special Intervention Unit to define national counter terrorist police tactical units. Depending on the country, a PTU's missions can include surveillance and observation of suspected criminals and terrorists.
For "certain counter terrorism operations, such as hostage rescue, there is a significant convergence of roles, tactics and force when employed in either an armed conflict or policing role". Aside from counter-terrorism, the roles of police and military units differ in that the role of military units can result in the use of the maximum permissible force against enemy combatants while the role of police units is to use only minimal force sufficient to subdue suspected criminals, including negotiation.