SWAT team

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A unit within a police force that is trained to deal with situations of unusual danger, especially when requiring aggressive tactics or enhanced firepower, as in rescuing hostages, thwarting terrorist attacks or assassinations, and subduing heavily armed suspects.

from the GNU version of the Collaborative International Dictionary of English.

• noun a special group of police trained to deal with unusually dangerous or violent situations, and having special weapons, such as rifles more powerful than those carried by regular police officers. They are employed, for example, in situations when hostages are being held, or heavily armed persons need to be captured. Called also SWAT or S.W.A.T..

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a squad of policemen who have been trained to deal with violent and dangerous situations