When the Vietnamese ambassador to the US, Le Cong Phung, flew to Hawaii earlier this month to confer with the commander of American forces in the Pacific, Admiral Robert Willard, he carried a succinct message: 'Beware of China.'
In more diplomatic language, said US and Vietnamese officials, the ambassador asserted: 'Vietnam and the US should work together to counter China's territorial claims and attempts to hamper free navigation in the South China Sea.'
Willard, whose Pacific Command is charged with military relations with China - and deterring Chinese aggression if those relations turn sour - was said to be receptive.
The US and Vietnam have been gradually forging a reconciliation that can only be called remarkable, given the long war they fought from 1955 to 1975.
Phung reflected Hanoi's point of view and the long memories of the Vietnamese. Feudal China occupied large parts of Vietnam for a thousand years; more recently, China attacked Vietnam in 1979 and fought skirmishes after that.
For the United States, China's belligerence has been intensifying. Beijing seems bent on driving US forces and influence out of Asia. US commanders have quietly but repeatedly cautioned the Chinese not to miscalculate, as the US intends to remain a Pacific power.
To underscore the emerging security relations between the US and Vietnam, the 13th Air Force at Hickam Air Force Base in Hawaii plans to deploy frontline engineers to Vietnam this summer to work with the Vietnamese on refurbishing schools and hospitals.
