China's top diplomat Wang Yi to visit Vietnam from Thursday

According to Reuters, "He is expected to attend a Vietnam-China inter-government meeting in Hanoi on Friday," one of the sources said.

Vietnam's and China's foreign ministries did not immediately respond to a requests for comment.

China has had traditionally strong ties with Vietnam since diplomatic relations were established in 1950, despite a brief war in 1979.

China is Vietnam's largest trading partner and a vital source of imports for its manufacturing sector.

China's Commerce Minister Wang Wentao on Monday during a visit to Vietnam pledged to further open the Chinese market to Vietnamese agricultural products as the two countries seek to deepen trade ties, according to Vietnam's Ministry of Industry and Trade.

Reuters last month reported that Vietnamese and Chinese officials were preparing for a possible trip by Chinese President Xi Jinping to Hanoi. At the time, plans were for the trip to take place at the end of October or in early November. Three Hanoi-based diplomats subsequently said the visit was likely to be postponed to December.

Bilateral trade between Vietnam and China rose 5.5% last year to $175.5 billion, with shipments from China to Vietnam accounting for 67%, according to the ministry.