During the short visit to Vietnam, Biden is expected to work on deepening ties

US President Joe Biden hailed closer ties with Vietnam on Sunday as the two countries struck a deal to deepen relations and cooperation on strategic supplies in the face of growing competition from China.

Biden flew from the G20 summit in New Delhi to meet the leader of Vietnam's ruling Communist Party, Nguyen Phu Trong, 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 China's increasing diplomatic influence, while securing supplies of strategically important resources from friendly countries.

"This can be the beginning of even a greater era of cooperation," Biden said as he met Trong, Vietnam's paramount leader.

"Vietnam and the United States are critical partners at what I would argue is a very critical time."

The deal puts the United States on a par with China -- as well as Russia, India and South Korea -- in the Vietnamese hierarchy of diplomatic relations.

"We're deepening our cooperation on critical emerging technologies, particularly around building a more resilient semiconductor supply chain," Biden said.

Trong thanked Biden for his contribution to improving US-Vietnamese ties and said his country would work hard to implement the new agreement.

Jon Finer, the US deputy national security advisor, told reporters ahead of Biden's arrival that talks would also cover 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.

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

Although it is 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.

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 said he had raised human rights in his meeting with Trong and pledged to "continue our candid dialogue in that regard".

Vietnam has a dire 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.

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.

US President Joe Biden will make a one-day trip to Hanoi