During the early afternoon of 18 February two platoons from Lt. Col. Ackerson's 1/5th Cavalry came under heavy fire while patrolling. With the platoons pinned down, Ackerson reinforced with two rifle companies, but fire from earthworks cut them apart, and casualties were left where they fell. At the end of the day the Americans broke contact to retrieve their dead and wounded. The troops labeled the sector where the roughest fighting had taken place the "Iron Triangle", because of its shape (not to be confused with the better-known Iron Triangle near Saigon). The fighting continued on the 19th. Company B, 2/12th Cavalry joined Company C, 2/5th Cavalry on a sweep southwest of the Iron Triangle. When one of the companies drew fire in the morning, the other attempted to turn the enemy's flank but ran into more VC. After breaking contact and calling in artillery and air strikes, the two companies attacked, killing 36 VC and forcing the remainder to withdraw. 1/5th Cavalry, meanwhile, renewed its assault into the triangle, with two companies moving west while the third blocked. But the VC stood their ground, stalling the advance. At dark, the 1/5th Cavalry broke contact to remove their wounded. The next day, 20 February, Lynch ordered Ackerson to continue his attack. Following a morning artillery strike, one of the companies came under fire from a strongpoint no more than 100m from the scene of the previous day's fighting. The Americans pulled back and called in artillery. In the afternoon a 2/12th Cavalry unit fought a running battle that left 23 VC dead before the VC withdrew.