Many of the RAAF's C-130s were redeployed to South Vietnam shortly before the end of the war in 1975. The rapid North Vietnamese advance during the Spring Offensive displaced hundreds of thousands of South Vietnamese civilians, and the Australian Government deployed a detachment of Hercules to Saigon in March 1975 as part of an international aid effort coordinated by the United States. This force, which was designated Detachment S, had an average strength of seven C-130s and about one hundred air and ground crew, and was initially used to transport civilian refugees away from the front lines. After South Vietnamese soldiers were reported to have been transported alongside civilians, Prime Minister Gough Whitlam directed that the Hercules were to only carry humanitarian cargo. As the North Vietnamese advanced on Saigon, Detachment S was moved to Bangkok in Thailand, but continued to fly into South Vietnam each day. Overall, Detachment S had carried 1,100 refugees and 900 tonnes of supplies by the end of the war. On 4 and 17 April, aircraft of the detachment flew 271 orphaned children to Bangkok as part of the US-led Operation Babylift. In late April, two of No. 37 Squadron's C-130Es were assigned to the United Nations to transport supplies throughout Southeast Asia; this force was designated Detachment N. The C-130Es began operations on 3 May, and were mainly used to fly supplies into Laos. The aircraft transported cargo between Thailand, Butterworth, Hong Kong and Singapore; by the time this mission ended in early June, the two Hercules had conducted 91 sorties for the UN. Aircraft of Detachment S evacuated Australian embassy personnel from Phnom Penh in Cambodia, as well as Saigon, shortly before they fell to Khmer Rouge and North Vietnamese forces in April 1975, after which the force returned to Australia. Detachment N also evacuated the Australian embassy in Vientiane, Laos, during early June 1975.