from the terror of the Pol Pot era. NADK forces consisted of former RAK troops, conscripts forcibly recruited during the 1978/79 retreat, and personnel pressed into service during in-country raids or drawn from refugees and new volunteers. Military observers and journalists estimated around 40,000 and 50,000 NADK combatants, which were considered to be "the only effective [anti-Vietnamese] fighting force". In 1987 the opinion that the NADK was "the only effective fighting force" opposing the Vietnamese was expressed by foreign observers. In an interview published in the United States in May 1987, Sihanouk reportedly said, "without the Khmer Rouge, we have no credibility on the battlefield... [they are]... the only credible military force." Led by senior figures such as Son Sen, Khieu Samphan, Ieng Sary and Ta Mok with an unclear hierarchy and loyalty structure, the NADK units were "less experienced, less motivated, and younger" than the early to mid 1970s generation of Khmer Rouge fighters. The NADK only gained limited success, despite their use of terror against civilians, murder and destruction of property and economic resources, and invoking traditional Cambodian hatred of the Vietnamese as a means to recruit personnel; most Cambodians preferred to live under Vietnamese occupation rather than endure another Khmer Rouge reign. The NADK divided Cambodia into four autonomous military zones. As the bulk of combatants were stationed at the Thai border, countless Khmer Rouge sanctuaries existed countrywide. This kept Cambodia "in a permanent state of insecurity" until the late 1990s. The NADK received most of its military equipment and financing from China. Sources suggest Chinese aid in between US$60 Million and US$100 Million a year, to as high as US$1 million a month, arrived via two infiltration routes. One of them ran south from Thailand through the Dangrek Mountains into northern Cambodia. The second ran north from Trat, a Thai seaport in the Gulf of Thailand. Khmer People's National Liberation Armed Forces The Khmer People's National Liberation Armed Forces (KPNLAF) was the military component of the Khmer People's National Liberation Front (KPNLF). The KPNLAF was formed in March 1979 and loyal to Son Sann. It was consolidated by General Dien Del (Chief of Staff) from various anticommunist groups, former Khmer Republic soldiers, refugees, and retreating military and insurgency combatants at the Thai border. The KPNLAF initially lacked a central command structure, as personal allegiance and loyalty only functioned in various warlord bands. These bands focused on