Two other measures to strengthen his sector of JAMESTOWN were utilized by the Marine division commander. On 18 April, he asked General O’Daniel to reconsider the no-fire zone recently established by the corps commander. General Selden, who had received reports of Chinese use of the sanctuary located within Marine Corps territory--for firing positions and assembly areas primarily--recommended, after I Corps had refused him permission to fire into the haven, a redrawing of the O’Daniel line to coincide more closely with the boundaries established by the UN. Approval along the lines submitted by the division was given by I Corps that same day. The second measure employed by General Selden was use of an additional defensive line, WYOMING FORWARD. This position, closely paralleling JAMESTOWN in the KMC and 5th Marines sectors, added depth to the sector defenses. A unique rescue and recovery operation also came into existence about this time. On 19 April the division ordered the 5th Marines, occupying the center regimental sector, to organize a tank-infantry force for rescue of the United Nations Truce Team, should such action become necessary. The regimental plan, published on 22 April, utilized a reinforced rifle company-tank company organization directly supported by organic 5th Marines 4.2-inch mortars and 1/11. The Everready Rescue Force, from the regimental reserve, occupied the high ground (OP 2) east of and dominating Panmunjom. In addition to setting forth organizational details of the task unit, the 5th Marines Operational Plan 6-52 specified the method of operation for the rescue force. Taking advantage of the peace corridor in the western end of the center sector, a Forward Covering Force would speed tank-riding infantry to the high ground one-half mile beyond the objective, Panmunjon. Following would be the Pick-Up Force, from the 1st Tank Battalion Headquarters Platoon, which would retrieve the principal UN delegates and take them quickly to the assembly area two miles to the rear of the MLR. A Rear Covering Force, composed of a tank-infantry element, would follow the Pick-Up force both on its way towards the objective and on the return trip. Withdrawal of both covering forces was regulated by a series of phase lines. _Marine Air Operations_[52] [52] Unless otherwise noted, the material in this section is derived from: _PacFlt EvalRpt_ No. 4, Chaps. 9, 10; 1st MAW, HMR-161, VMO-6 ComdDs, Apr 52; Lynn Montross, _Cavalry of the Sky--The Story of U. S. Marine Combat Helicopters_ (New York: Harper & Brothers, 1954), hereafter Montross, _SkyCav_, quoted with permission of the publishers.