BEIJING (Reuters) - China's President Xi Jinping told a special envoy from Vietnam on Wednesday that both countries should be "friendly to each other" to help mend ties after a flare-up over sovereignty in the South China Sea, the official Xinhua news agency said.

The visit to Beijing by Le Hongh Anh, a member of the Vietnamese Communist Party's powerful politburo, is the first sign of a concerted effort to heal the rift between the two countries, which share annual trade worth US$50 billion (S62.35 billion).

"(I) hope the Vietnamese will make joint efforts with the Chinese to put the bilateral relationship back on the right track of development," Xinhua quoted Mr Xi as telling Mr Le Hong Anh. "A neighbour cannot be moved away and it is in the common interests of both sides to be friendly to each other."

Earlier, Mr Liu Yunshan, a member of China's elite Politburo Standing Committee, was quoted by Xinhua as telling the visitor that both sides should bring bilateral relations back on track.

"China-Vietnam relations for a while have been tense and difficult, which we do not want to see," Mr Liu said, adding that Mr Le Hongh Anh's visit reflected the Vietnamese government's"political will to mend and develop bilateral relations".

Under an agreement reached between Mr Liu and the visitor, China and Vietnam will earnestly implement a basic guideline for the resolution of China-Vietnam maritime issues signed in October 2011, Xinhua said. They agreed to seek lasting solutions acceptable to both sides, studying joint exploration of the South China Sea and avoiding actions that complicate disputes, it added.

Relations between the two Communist neighbours sank to their lowest level in three decades this year after China deployed a US$1-billion oil rig in waters Vietnam claims as its exclusive economic zone.

China moved the rig on July 16, saying its mission was complete. Rare protests in Vietnam turned violent in several industrialised provinces in May, with bloody clashes between Vietnamese and Chinese workers in central Ha Tinh province killing at least four people and wounding at least 100. About 4,000 Chinese workers fled Vietnam.

Vietnam, which relies heavily on Chinese materials for its manufacturing sector, has good economic reasons for mending ties with its giant northern neighbour, but perceived concessions to Beijing could prove deeply unpopular at home. The dispute has seen Vietnam forge closer alliances with other countries locked in maritime rows with China, including the Philippines and Japan.