sentences:  Known for his pro-Chinese sympathies, Hoan reached the peak of his career in the early 1960s when North Vietnam temporarily adopted a pro-Chinese attitude in the Sino-Soviet dispute.In 1963, when Foreign Minister Ung Văn Khiêm was replaced by the more pro-Chinese Xuân Thủy, Hoan headed the International Liaison Department of the VWP CC.In 1965–1966, however, Soviet-DRV relations started to improve, accompanied by increasing tension between Hanoi and Beijing.