The U.S. State Department says human rights conditions have deteriorated in China and that Vietnam also continues to severely restrict political rights and freedom of expression.
The judgments were made in the department's annual assessment of human rights around the world released Thursday.
The department hailed "remarkable" improvements in Myanmar, with the releases of hundreds of political prisoners and the participation of its most famous former detainee, democracy leader Aung San Suu Kyi, in elections.
The report criticized Sri Lanka for disappearances and killings by pro-government paramilitary groups despite the end of the island nation's civil war in 2009.
The department said conditions remain extremely poor in North Korea, where an estimated 130,000-200,000 people are detained in political penal labor camps.