"Abu Ghraib was only the tip of the iceberg," said Reed Brody, special counsel for Human Rights Watch, in a statement. "It's now clear that abuse of detainees has happened all over -- from Afghanistan to Guantanamo Bay to a lot of third-country dungeons where the United States has sent prisoners."
The statement was released a day before the anniversary of the first pictures of U.S. soldiers abusing Iraqi prisoners at Abu Ghraib becoming public.
Washington says the abuse of prisoners was an exception and punished those held responsible, but critics say the United States now "outsources" torture of terror suspects to third countries where such methods are still used.
In its statement, HRW said those nations included "quite a few other places we don't even know about."
The statement said nine detainees died in U.S. custody and 11 others "disappeared" elsewhere.