A young girl looks out and smiles under a poster welcoming US President Barack Obama on the door of a shop in Hanoi, Vietnam on Sunday. Obama is expected to arrive in Hanoi on Monday for a three-day state visit to Vietnam. Photo: AP

US President Barack Obama's first visit to Vietnam will not affect ties between Beijing and Hanoi, but the timing of his visit ahead of a South China Sea ruling can be seen as a gesture of support for Hanoi in the sea disputes, analysts said.

During his three-day visit which started Monday, Obama is scheduled to meet Vietnam's three highest-ranking officials, and hold talks with Nguyen Phu Trong, General Secretary of the Communist Party of Vietnam, the Xinhua News Agency reported.

They will discuss a wide range of issues including politics, security, investment, trade, the Trans-Pacific Partnership (TPP) and human rights, Xinhua reported.

Though Obama's Vietnam trip shows the US is positioning Vietnam as a security partner instead of an enemy after the Vietnam War as they need each other to contain China on several issues, including the South China Sea, Sino-Vietnamese ties will not be affected by the visit, said experts.

Closer ties with the US only means Vietnam lifts the position of the US for practical needs, but it will never play down the irreplaceable bond with China, said Zhu Zhenming, a research fellow on Southeast Asia studies with the Yunnan Academy of Social Sciences.

Obama is the third serving President to visit Vietnam, following Bill Clinton in 2000 and George W. Bush in 2006, since the two countries established bilateral diplomatic relations in July 1995.

Tricky timing

While 2015 marked the 20th anniversary of normalized diplomatic ties between Washington and Hanoi and the 40th anniversary of the end of the Vietnam War, Obama has picked a time to visit when the South China Sea issue is under intense global scrutiny with the expected release of the ruling in the sea arbitration case filed by the Philippines.

"Vietnam is the only Southeast Asian country that could truly cause some trouble for China and Obama's visit is meant to assure that it is the strongest backup for Vietnam in the dispute," Zhuang Guotu, head of the Center of Southeast Asian Studies at Xiamen University, told the Global Times.

The US has already successfully wooed its ally Japan to become involved in the disputed South China Sea, and if Vietnam could publicly oppose China on this issue, the US will have more chance to interfere in the region, Zhuang added.

Counterbalance China

Apart from Obama's visit, US Secretary of State John Kerry visited Myanmar on Sunday to meet with key leaders in Nay Pyi Taw, which was perceived by some observers as a move to further expand US influence in the Asia-Pacific region and to counterbalance China.

In addition, support to fully remove or further ease the US ban on weapons sales to Vietnam within the US administration and on Capitol Hill has grown, in efforts to bolster US-Vietnam ties to counter a rising China, Reuters said.

Though the US still has concerns, including over human rights, before it may consider fully removing the weapons ban after it was partially lifted in 2014, there is a strong possibility it could be removed, Zhu Feng, director of the Collaborative Innovation Center of South China Sea Studies at Nanjing University, told the Global Times.

Hanoi released Nguyen Van Ly, a Catholic priest and one of Vietnam's longest-serving prisoners, on Friday, which Zhu noted was a signal from the Vietnam side ahead of Obama's visit.

As part of the payoff for the lifting, Vietnam might allow the US to access its strategic Cam Ranh Bay in the South China Sea, The New York Times reported Thursday.

However, the US will be very cautious over lifting the ban as there will be strong opposition from over 3 million Vietnamese-Americans in the US, who try to subvert the rule of the Communist Party of Vietnam, said Zhuang.

Separately, Obama and Vietnam's leaders will also discuss a wide range of issues including the TPP, in which Vietnam could be the biggest winner among the 12 signatories, as it heavily relies on exports, Bloomberg reported in October 2015. Vietnam's economy could be boosted by 11 percent, or $36 billion over a decade by the slashing of tariffs on thousands of products, the report said.

However, the agreement will shrink Sino-Vietnam economic ties and put more pressure on China's sliding economy after it was ratified by all the 12 signatories that comprises 40 percent of global GDP, said Zhuang.