Three task-force-grouped SWAT units (referred to as Peace Enforcing Special Service Forces or "Wei-An" Forces(:zh:維安特勤隊) comprise the 1st, 4th and 5th Special Police Corps. The mission of the "Wei-An" Forces include counter-terrorism, counter-hijacking, high-profile hostage rescue, and presidential protection. In recent years they have also been involved in the arrest of heavily armed fugitives. The uniforms and equipment of the Wei-An units are similar to local SWAT units, which are referred to as Thunder Squads. The Thunder Squads are subordinate to local police departments. However, the "Wei-An" Forces are the only police units equipped with V-150S armor vehicles and M998 Humvee, which were transferred from ROC Army after the 2004 shoot out with Zhang Xi-Ming (:zh:張錫銘).