On 18 December 1972, the Linebacker II campaign was initiated when negotiations in the Paris peace talks stalemated. Participating carriers were "Ranger", , , , and . In an intensified version of Operation Linebacker, bombing of North Vietnam above the 20th parallel and reseeding of the mine fields were resumed, and concentrated strikes were carried out against surface-to-air missile and antiaircraft artillery sites, enemy army barracks, petroleum storage areas, Haiphong naval and shipyard areas, and railroad and truck stations. Navy tactical air attack sorties were centered in the coastal areas around Hanoi and Haiphong, with 505 Navy sorties were carried out in this area. These operations ended on 29 December when the North Vietnamese returned to the peace table; on 27 January 1973, the Vietnam cease-fire came into effect, and "Oriskany", "America", "Enterprise", and "Ranger", on Yankee Station, cancelled all combat sorties.