With the 1st Marine Division still responsible for security, it was a relief to General Smith when the distinguished visitors departed unharmed. Not all the mines had been removed from the streets as yet, and it was suspected that snipers might still be lurking in the ruins.[458] [458] O. P. Smith, _Chronicle_, 29 Sep 50. _Crumbling of NKPA Resistance_ Although more hard fighting lay ahead in the Inchon-Seoul operation, X Corps alerted its major units on 29 September to the possibility of a new amphibious landing on the east coast of Korea. This was one of the earliest announcements of the planning which led to the Wonsan landing and the advance to the Chosin Reservoir, but the history of those events belongs in the next volume of this series. The new operation was suggested by the rapid disintegration of the main body of the NKPA invasion forces. In a single day, 26 September, elements of the 1st Cavalry Division had advanced more than 100 miles; and a total of about 23,600 prisoners were taken by the Eighth Army before the end of the month. Enemy resistance was still encountered, to be sure, and sometimes it was of a desperate nature as Red Korean troops fought to escape encirclement. But all hope and heart had gone out of the Communist cause. One Eighth Army column sliced across the peninsula to Kunsan while other spearheads drove northward and ROK units pushed up the east coast nearly to Samchok. NKPA opposition was crumbling everywhere as demoralized invasion troops threw away their weapons and changed to civilian clothes in the hope of making their way to North Korea through the ever tightening Eighth Army cordon.[459] [459] U. S. MilAcad, _Operations in Korea_, 18–19. The X Corps troops in the Seoul area had enough on their hands to finish the old operation before starting a new one. 1st Marine Division OpnO 13-50, issued at 2000 on 29 September, provided for the securing of the captured city by these means: (1) a continuation of the attack to the east; (2) the conduct of reconnaissances in force to the north and northwest; (3) the relief of elements of the 7th Infantry Division north of the river Han; (4) the seizure of prescribed blocking positions.[460] [460] O. P. Smith, _Notes_, 318. The Division plan of maneuver called for the three Marine rifle regiments to take blocking positions forming a rough semi-circle defending Seoul from three sides--the 5th Marines to the northwest, the 7th Marines to the north, and the 1st Marines to the northeast. Responsibility for the area north of the Han river and west of the Pukhan River had passed to the 1st Marine Division, and at 1500 on 30 September the following missions were assigned by OpnO 14-50: