 Communist forces were rapidly swelled by rural Cambodians, attracted by Sihanouk's name and angry at the casualties caused by American bombing.For Sihanouk, the support of the communists enabled him to continue his bid to regain power and to secure the backing of the North Vietnamese (whose forces occupied swathes of rural Cambodia) and of China.However, it is likely that Sihanouk was conscious that the more hardline elements of the Khmer Rouge would seek his eventual removal; his plan therefore depended on attracting American support for his 'national unity' movement.