Members of Congress have apologised to a Canadian who was seized in New York in 2002 by US officials and sent to Syria, where he says he was tortured.
Canada has urged the US to remove him from its watch list
Syrian-born Maher Arar told a congressional hearing his 10 months in a Syrian jail had been "hell".
Mr Arar appeared by video link from Canada because he remains on a US government watch list.
A Canadian government inquiry cleared him of any involvement in terrorism. Syria denies that he was tortured.
Mr Arar appeared on a giant screen before a joint hearing of House of Representatives committees into "extraordinary rendition".
This term refers to a highly secretive process by which US intelligence agencies send terror suspects for interrogation by security officials in other countries, where they have no legal protection or rights under US law.
Mr Arar described being detained by US homeland security agents at New York's JFK airport and of later being sent by private jet to Syria, where he spent 10 months in a prison cell he described as a grave.
"I was beaten with an electrical cable and threatened with a metal chair, the tyre and electric shocks. I was forced to falsely confess that I had been to Afghanistan," he said.
"When I was not being beaten I was put in a waiting room so that I could hear the screams of other prisoners. The cries of the women still haunt me the most."
Mr Arar was later released without charge.
Among those offering their apologies at the hearing was Congressman Jerrold Nadler from New York.
"On behalf of my fellow citizens I want to apologise to you, Mr Arar, for the reprehensible conduct of our government for kidnapping you, for turning you over to Syria - a nation that our own state department recognises as routinely practising torture. This conduct does not reflect the values of the American people," he said.
Rep Dana Rohrabacher also apologised, saying the US should be ashamed of what happened to Mr Arar.
But, he said, "that is no excuse to end a programme which has protected the lives of hundreds of thousands, if not millions, of Americans... We are at war. Mistakes happen. People die".
The Canadian government has formally apologised to Mr Arar and offered him compensation amounting to more than $10m (US $10.2m, £5m).
Canadian police had labelled him an Islamic extremist.