In his first visit to the key southeast Asian country as the top US diplomat, Blinken met Prime Minister Pham Minh Chinh, saying during that the past decade there has been "extraordinary progress" in the bilateral relationship.

Noting that the two nations mark the 10th anniversary of their formal partnership this year, Blinken told reporters Washington had "hope to be able to take it to an even higher, higher level."

Chinh said both sides were "looking to further strengthening, further elevating our bilateral ties to a new height," after a phone call last month between President Joe Biden and the head of Vietnam's ruling Communist Party, Nguyen Phu Trong.

Vietnam is a crucial Southeast Asian trading partner that Washington is looking to bolster ties with as it works to balance China's growing assertiveness in the region and beyond.

The diplomatic anniversary and the Biden-Trong call could lead to a meeting between the two in July or other high-level meetings, analysts say. It is still unclear, though, when an upgrade of formal ties could be agreed.

Blinken, who is to meet with top Vietnamese officials, including Trong, broke ground on a new US embassy compound in Hanoi after meeting the prime minister.

The US diplomat heads to Japan on Sunday for a meeting of foreign ministers of the Group of Seven wealthy nations.

The United States faces challenges in Southeast Asia in building a coalition to counter China and deter any potential action by Beijing against Taiwan. Many countries in the region are reluctant to antagonise their giant neighbour, which is not just a military power but also a key trading partner and source of investment.

For Hanoi, it has been a difficult balancing act, being open to more cooperation with Washington without upsetting Beijing, even though Vietnam has been alarmed by China's growing military claims in the South China Sea.

The diplomatic calculus is further complicated by increasingly close relations between Beijing and Moscow, which last year declared a "no limits" partnership shortly after Russia's invasion of Ukraine.

But while the United States has been keen to push for stronger ties with Vietnam, Hanoi has been cautious, fearing the impact an upgrade of relations with Washington could have on its relations with Beijing.