Conflict+With+Neighbors

Vietnam's 1978 invasion of Cambodia in particular, together with its increasingly tight alliance with the Soviet Union, appeared to confirm suspicions that Vietnam wanted to establish a Soviet-backed hegemony in Indochina. Vietnam's invasion of Cambodia also heightened tensions that had been building between Vietnam and China. Beijing, which backed the Khmer Rouge regime in Cambodia, retaliated in early 1979 by initiating a brief, but bloody border war with Vietnam.

Tensions with China began to grow during the Chinese Cultural Revolution, and by 1975, Beijing had become increasingly critical of Hanoi's growing ties with Moscow. Over the next 4 years, Beijing's growing support for Cambodia's Khmer Rouge, which in 1978 initiated bloody attacks across its border with Vietnam, reinforced Vietnamese suspicions of China's motives.

Vietnam's tensions with its neighbors, internal repression, and a stagnant economy contributed to a massive exodus from Vietnam. Fearing persecution, many ethnic Chinese in particular fled Vietnam by boat to nearby countries. Later, hundreds of thousands of other Vietnamese nationals fled as well, seeking temporary refuge in camps throughout Southeast Asia.

http://www.state.gov/r/pa/ei/bgn/4130.htm