US President Barack Obama has held historic talks at the White House with Vietnam's Communist Party leader, Nguyen Phu Trong.
It was the first such meeting since the two countries normalised relations 20 years ago.
Mr Obama said that despite differing political philosophies, the two countries were deepening co-operation.
Analysts say the US and Vietnam are seeking stronger ties in the face of an increasingly assertive China.
This month marks 40 years since the end of the Vietnam war.
"Obviously, there has been a difficult history between our two countries in the 20th Century and there continues to be significant differences in political philosophy and political systems," Mr Obama said.
Mr Trong described the talks as "cordial, constructive, positive and frank".