The US State Department said it was monitoring events in Vietnam closely, and urged restraint from all parties.
White House spokesman Jay Carney said:
We support the right of individuals to assemble peacefully to protest.
(Such disputes) need to be resolved through dialogue, not through intimidation
We again urge dialogue in their resolution.
The current crisis erupted within days of a week-long visit to Asia by President Barack Obama in late April in which he pledged that Washington would live up to its obligation to defend its allies in the region.
More top news
Ted Robbins is "doing well" and is expected to be "fit and healthy soon" after collapsing on-stage during Phoenix Nights Live, his wife said
Doctors in India have carried out what is believed to be the world's first double hand transplant to be performed on a non-white patient.
Prince George is not only heir to Britain's throne, but a future long distance runner too, if his uncle has anything to do with it.