After the early May change of lines, the Chinese lost little time in testing the new UNC defenses. Shortly after 0200 on 15 May, the CCF directed a two-battalion probe on the Carson-Elko-Vegas trio and the Berlin-East Berlin outposts newly held by the Turkish brigade. Supported by heavy concentrations of mortar and artillery, one battalion of enemy soldiers moved against each of the two major defense complexes. Marine Company C tanks, occupying the firing slots that night, accounted for heavy enemy losses in the action, estimated at 200 CCF killed and 100 wounded. Assisting the TAFC Field Artillery Battalion in throwing back the attack were 1/11, 2/11, and 4/11 which sent 3,640 rounds into the sharp four-hour engagement. The TAFC defense was further reinforced later that day with 21 air strikes against hostile personnel and weapons positions north of the Turkish sector. Adding their weight to the clash, 3/11 and the rocket battery also brought their guns into action, for a combined 5,526 Marine rounds[428] dispatched against the enemy. [428] Total ammunition expenditure by the 11th Marines and the 25th Division artillery batteries was 11,527 rounds, to the Chinese output of approximately 10,000 rounds. 11thMarDiv ComdD, May 53, p. 13. It was not until 25 May, after the UNC had made its final offer at the truce talks, however, that CCF artillery really began to open up on the Nevada complex. The increased activity by hostile pieces, during the 25–27 May period, was duly noted by the artillery Marines who laconically reported, “Operations followed the recent pattern: enemy shelling of the Turkish Brigade increased during the afternoon; no contacts were reported.”[429] [429] 11thMar ComdD, May 53, dtd 27 May, p. 19. This latter situation changed abruptly on 28 May. Beginning at 1800, major elements of the Chinese 120th Division launched simultaneous attacks over 17,500 yards of I Corps front that stretched from COP-2 eastward to that consistent trouble-spot, the Nevada Cities, on to the Berlins, and finally the Hook area in the adjacent Commonwealth Division sector. Supported by heavy artillery fires, one CCF battalion moved in towards Carson and Elko. Another battalion,[430] under cover of smoke, attacked central COP Vegas, while a third struck Berlin and East Berlin on the right flank. Three hours after the initial attack, defenders at Carson and Elko were engaged in hand-to-hand combat with the Chinese. [430] Some historians indicate that the 120th Division initially sent four battalions forward in the action, with two against the main objective, Vegas. Hermes, _Truce Tent_, p. 463.