中ソ国境紛争
The already strained Sino-Soviet relationship deteriorated sharply in 1959, when the Soviets started to restrict the flow of scientific and technological information to China. The dispute escalated, and the Soviets withdrew all of their personnel from China by August 1960, leaving many construction projects dormant. In the same year, the Soviets and the Chinese began to have disputes openly in international forums. The relationship between the two powers reached a low point in 1969 with the Sino-Soviet border conflict, when Soviet and Chinese troops met in combat on the Manchurian border.