During the Vietnam War, the Chinese claimed that the Soviet Union would betray North Vietnam. Chinese Premier Zhou Enlai told Lê Duẩn that the Soviets would lie to them to improve its relationship with the United States. According to Zhou this policy was enacted following Alexei Kosygin's departure from Vietnam in 1965. Lê Duẩn did not accept this view and at the 23rd Party Congress (which China boycotted) he referred to the Soviet Union as a "second motherland". Because of his statement, China immediately began to cut its aid to North Vietnam. According to the first secretary at the Soviet embassy to China, the North Vietnamese saw the Chinese actions as an attack on them. At the Chinese Communist Party's 45th anniversary, instead of a communique by Hồ Chí Minh, Phạm Văn Đồng and Lê Duẩn as had happened at the 44th anniversary, the Vietnamese Central Committee offered official greetings, but without signatures from top-level officials.