At 18:30 a unit of the 3rd Brigade, 25th Infantry Division engaged an enemy unit north-northwest of Saigon killing 12 and capturing five individual and two crew-served weapons. At 23:39 five 122mm rockets hit northern Saigon killing six civilians. On 21 June at 00:15 five 107mm rockets hit Tan Son Nhut Air Base killing six civilians. At 11:45 a unit of the 3rd Brigade, 101st Airborne Division engaged two reinforced enemy companies near Hiệp Hòa, the enemy withdrew at 21:30 leaving 35 dead; U.S. losses were one killed. On 22 June at 02:15 eight mortar/rocket rounds hit the Saigon docks causing minor damage. On 23 June a unit of the 1st Brigade, 9th Infantry Division received fire southeast of Bến Lức and returned fire supported by artillery, airstrikes and AC-47 fire. The enemy withdrew at 23:45 and a sweep the next morning found 41 PAVN/VC dead, two captured and 11 individual and five crew-served weapons; U.S. losses were four killed. On 24 June at 09:20 an OH-6 Cayuse light observation helicopter was shot down east-northeast of Tân An killing both crewmen. At 10:20 a unit of the 3rd Brigade, 9th Infantry Division engaged an enemy force in the same area, other units reinforced and the enemy withdrew at 23:00. A sweep of the area the next day found 46 PAVN/VC dead and 13 weapons captured; U.S. losses were five killed. A United States Air Force (USAF) forward air controller (FAC) saw enemy forces south-southwest of Phú Cường and directed airstrikes onto the area. A subsequent sweep by the 17th Cavalry Regiment found 20 PAVN/VC dead. From 23 June 4th Battalion, Royal Australian Regiment (4 RAR/NZ) joined the operation, deploying to the Biên Hòa-Long Khánh Province border to assist 1st Battalion, Royal Australian Regiment (1 RAR). 4 RAR/NZ's role was to deny enemy infiltration routes into Saigon and to identify rocket-launching sites. Only one contact was made by the New Zealand infantry company of 4 RAR/NZ. On 3 July 1 RAR left the operation. On 25 June at 07:55 two UH-1s collided west of Bearcat Base killing 12 U.S. Army personnel, 16 Thai soldiers and one ARVN soldier.