The visit to Beijing will take place from Oct 30 to Nov 2 the government said, without elaborating. It was also reported in Chinese state media on Tuesday.

Trong, 78, on Sunday sent a message to Xi congratulating him on his precedent-breaking third term as party chief, expressing hope of “further strengthening political trust, and setting a great direction for future development of the relationship between the two countries.”

China is Vietnam’s largest trading partner and a key source of imports for its fast-growing economy, including raw materials and machinery for its crucial manufacturing sector.

Bilateral trade rose 10.2% in the first nine months of this year from a year earlier to $132.38 billion, according to official Vietnamese data, nearly 70% of that imports to Vietnam.

Though the two neighbours have a long history of mistrust and territorial disputes, including over islands and waters in the South China Sea, their Communist parties remain officially close.

Like Xi, Trong has also stayed on as party chief beyond the usual tenure of one or two terms, cementing his influence in a party traditionally governed by consensus among its politburo and powerful central committee. His last trip abroad was to Russia.

Vietnam and China are among the last five communist-ruled states in the world, along with Cuba, Laos and North Korea.