Operational Maneuver Group
Introduced during theSecond World War by the Red Army, the Operational Maneuver Group (OMG) is part of Soviet and Russian land warfare doctrine, variations of which have been adopted by other armies. In its original form, the OMG was a highly mobile, self-contained, armored force, of at least division and usually corps strength. Its mission was to penetrate enemy lines, not to open a gap for slower forces as in blitzkrieg, but to penetrate to the enemy's rear area, and attack targets of opportunity until victory or defeat. The classic Soviet doctrine considered it having a one-way mission; it would rarely be reinforced or link up with other forces, unless those forces rolled up a broad front. 
In Western doctrine, a classic cavalry mission is to go behind enemy lines, scout and disrupt, but return. This was easier to achieve with horse cavalry than with tank-heavy forces, although it lends itself to air assault. In a short campaign such as the Gulf War, this essentially was the mission of the 101st Airborne Division.
NATO always feared the point at which the OMG would appear. They remembered the 1943 Battle of Kursk when the OMG struck just after the Soviet defenses had exhausted the Nazi breakthrough forces. .