Kerry, whose experiences during the Vietnam War inspired his political activism, hailed the relationship between the former enemies as "stronger than ever", on his first official visit to the nation as the top US diplomat.
"I can't think of two countries that have worked harder, done more and done better to try and bring themselves together to change history, and change the future," Kerry told students, businesspeople and reporters at an event in Ho Chi Minh City today.
The region is beset by political and territorial tensions, including bitter maritime disputes between an increasingly assertive Beijing and a number of its neighbours -- among them Vietnam.
Kerry is scheduled to meet Prime Minister Nguyen Tan Dung and Foreign Minister Pham Binh Minh in Hanoi to discuss deepening trade and security ties as part of his three-day visit.
Vietnam is on the "doorstep of another great transformation," he said, as negotiators inch closer towards signing the Trans-Pacific Partnership (TPP) -- a vast trade agreement currently under negotiation.
"Vietnam has the potential to become one of the US's leading economic partners in the region," Kerry said.
The TPP could help Vietnam to "maintain the momentum" for market reforms, particularly of its notoriously inefficient state-owned companies.
