Minister Harold Holt announced that Australia would increase its commitment to South Vietnam. In May 1966 the newly raised 5 and 6 RAR arrived in theatre as a part of the 1st Australian Task Force (1 ATF) in Phuoc Tuy Province, establishing a base at Nui Dat. After two months of constant patrolling by both battalions, 6 RAR was engaged in the action that would become a defining part of Australia's involvement in the war; the Battle of Long Tan. Fought on 18 August 1966, 108 men from D Company, 6 RAR fought a ferocious meeting engagement with the VC 275th Regiment, possibly reinforced by at least one North Vietnamese People's Army of Vietnam (PAVN) battalion, and D445 Battalion (between 1,500 and 2,500 personnel). After fighting for two and a half hours, D Company was surrounded on three sides. However, with the assistance of strong artillery support they were able to hold their position until the timely arrival of a relief force of infantry and armoured personnel carriers (APCs) finally forced the VC to break. In the words of the official historian, Ian McNeill, "D Company had achieved a stunning victory". In 1967, 2 and 7 RAR assumed responsibility in Phuoc Tuy from their predecessors and continued the extensive patrolling, and cordon and searches characteristic of this conflict. In August 1967, 7 RAR fought elements of the VC 3rd Battalion, 274th Regiment in the Battle of Suoi Chau Pha, where extensive artillery support again proved decisive. A third infantry battalion arrived in December 1967 as part of a significant expansion of 1 ATF. By the time of the Tet Offensive in 1968, 1 and 3 RAR were serving in theatre. During actions at Fire Support Base (FSB) Coral by 1 RAR and at FSB Balmoral by 3 RAR in May and June 1968, later known as the Battle of Coral–Balmoral, these two battalions of the regiment would fight battles with conventional attributes not seen since Kapyong. In June 1969, an infantry company from 5 RAR, then on its second tour, and supported by a troop of tanks and another of APCs fought a significant combined arms action against a battalion-sized force of PAVN regulars and VC local force troops during the Battle of Binh Ba. Following Binh Ba, the remainder of the regiment's service would be characterised largely by the policies of "Pacification" and "Vietnamization", with an emphasis on ambushing