Two bloggers were arrested, another blogger was denied release after he completed his prison sentence and nine people were convicted in human rights-related cases this week in advance of Clinton's two-day visit beginning Friday, The Washington Post said.
Analysts are split about what the Vietnamese actions mean, the Post said. Some said the activities are part of a crackdown on dissent as the country's Communist Party prepares for its first party congress in five years in January. Other analysts view the actions as part of an internal struggle within the Vietnamese Communist Party over its relations with the United States.
Bilateral relations have improved because the United States and Vietnam share a concern over the rise of China, observers said.
The actions prompted the U.S. Embassy in Hanoi to issue a statement of concern, the Post said.
Some U.S. experts expressed concern that progress in the U.S.-Vietnam relationship could suffer a setback if the Obama administration presses Vietnam too much on human rights.
For many non-government organizations and the human rights community, "Vietnam is a kickable China," said Brantly Womack, professor of politics at the University of Virginia. "It's an easy target."