The US has focused criticism on China, North Korea, Burma and Cuba in its annual human rights report.
The state department survey also condemned the activities of the Russian government for weakening civil society.
Pentagon officials have confirmed that Guantanamo detainees may still be kept in detention, even if they are found not guilty by a military tribunal.
They say detainees could be kept prisoner if they are considered a security risk.
If found guilty, they could also be held beyond any sentence laid down by the tribunal.
