US President Joe Biden arrived in Vietnam Sunday to deepen cooperation between the two nations, with semiconductors and rare earth minerals expected to be a key focus for talks.

Biden flew from the G20 summit in New Delhi to meet the leader of Vietnam's ruling Communist Party, Nguyen Phu Trong, on Sunday to sign off on a "comprehensive strategic partnership", Hanoi's highest level of diplomatic ties.

The goal of the short visit mirrors Biden's time at the G20 gathering -- shoring up support against Beijing's increasing diplomatic influence, while securing supplies of strategically important resources from friendly countries.

The two sides are expected to announce new cooperation on semiconductors, Jon Finer, the US deputy national security advisor, told reporters.

They will also hold detailed talks on supplies of rare earth minerals used in the manufacture of high-tech devices such as smartphones and electric car batteries.

The United States has said Vietnam -- with the world's second-largest deposits of rare earths after China -- has a key role to play as it looks to source less from China after supply chain shocks rocked the global economy in recent years.

Last month, Biden moved to restrict US investment in Chinese technology in sensitive areas including semiconductors, quantum computing and artificial intelligence.

For Vietnam, the upgrading of diplomatic ties is significant. It only has top-level ties with Russia, India, South Korea and China.

Although it will be careful to be seen as not taking sides between the United States and China, Vietnam shares US concerns about its neighbour's growing assertiveness in the contested South China Sea.

However, The New York Times reported just ahead of Biden's visit that Vietnam was secretly arranging to buy arms from Russia in contravention of US sanctions.

The report cited a Vietnamese finance ministry document that laid out plans to fund arms purchases from the Kremlin through a joint oil and gas project in Siberia.

AFP has contacted the Vietnamese government for comment.

Finer told reporters Sunday that Washington acknowledged Vietnam's decades-long military relationship with Russia.

But he said there was "increasing discomfort on the part of the Vietnamese with that relationship", and the new partnership would help Hanoi "diversify away from those partnerships" by allowing it to source from the United States and its allies.

There will be a welcome ceremony in Hanoi on Sunday, speeches by the two leaders and a news conference by Biden -- who on Tuesday awarded the top US military honour to a helicopter pilot who rescued four soldiers during the Vietnam War.

Hanoi's central Hoan Kiem Lake area, packed with families out for a weekend stroll, was adorned with American and Vietnamese flags ahead of the 80-year-old US president's arrival.

A souvenir shop nearby in the city's old quarter sold T-shirts with Biden's face emblazoned across the front.
"I think the US is a good friend to Vietnam," said Truong Thanh Duc, the shop's 61-year-old owner.

"With this visit of President Joe Biden, I think he will bring more business contracts and jobs to Vietnamese people."

Biden will be juggling strategic interests with the defence of human rights in Vietnam.

The Southeast Asian country has a dire human rights record. Government critics face intimidation, harassment and imprisonment after unfair trials, and there are reports of police torture to extract confessions, Human Rights Watch says.

While Biden has often criticised China's human rights record, he has largely stayed quiet on Vietnam and campaigners are fearful he may not press the subject.

National Security Advisor Jake Sullivan said before the trip that Biden would raise issues related "to freedom of expression, freedom of religion, and other basic human rights".

Nguyen Bac Truyen, a legal expert and religious freedom advocate who was sentenced in 2018 to 11 years in prison for subversion, said on Facebook on Saturday he had been released and allowed to travel to Germany with his wife.

Vietnam often releases political prisoners before US presidential visits.

Leaders at the G20 summit in India agreed on a joint declaration that papered over deep divisions on the war in Ukraine and tackling climate change, avoiding direct criticism of Moscow and any concrete pledge to phase out polluting fossil fuels.

Biden's Vietnam trip will also include a visit to a memorial to his friend John McCain, the former US senator shot down and held captive during the Vietnam War who in later years helped rebuild ties between the two countries.

(AFP)

U.S. President Joe Biden participates in a welcome ceremony hosted by Vietnam's Communist Party General Secretary Nguyen Phu Trong at the Presidential Palace in Hanoi, Vietnam, Sunday, Sept. 10. (AP)

Biden arrives in Vietnam to expand ties as China worries grow