Viet Nam's Communist Party chief will visit the United States this year, Washington's ambassador recently said, in a landmark trip underlining a rapid strengthening of ties between the two countries.

Nguyen Phu Trong would be the first party general secretary to visit the United States, which will also receive Viet Nam's Minister of Public Security.

Their trips will come amid recent advancements in ties between two countries that are currently marking 20 years since normalizing relations.

U.S. Ambassador to Viet Nam Ted Osius delivers a recent speech at the Viet Nam National University in Ha Noi

"Regular high-level visits help both sides understand and grow more comfortable with each other," U.S. Ambassador to Viet Nam Ted Osius said in a speech at a Ha Noi university.

"And this mutual understanding is turning talk into action."

The United States has been pouring in aid and assistance to Viet Nam in health, education, landmines clearance, scholarships and nuclear energy. More recently, activities involving their armed forces have stepped up.

Defence cooperation was previously limited by a lethal arms embargo, which Washington started to ease in October, enabling humanitarian exercises between both militaries late last year.

Analysts say Viet Nam's interests are in diversifying its ties beyond China, while the United States wants to court a new ally in Ha Noi as part of its moves to strengthen its influence in Asia as a counterbalance to Beijing's rise.

Osius said it was understandable Viet Nam would look to its "historic partners", but the United States would play its part.

"Viet Nam should have many friends, especially in a region as complex and dynamic as this one. However, the United States has much to offer...to enhance Viet Nam's security in the short, medium and long term,” he said