The White House said it was "deeply disappointed" at a UK Appeal Court ruling that revealed intelligence relating to torture allegations in the case of a former Guantanamo detainee.
Foreign Secretary David Miliband yesterday lost a bid to block public disclosure of information that revealed the "cruel, inhuman and degrading" treatment of Binyam Mohamed.
The White House said the ruling would make intelligence sharing with Britain more difficult in the future.
Binyam Mohamed, 31, an Ethiopian granted refugee status in Britain in 1994, claimed he was tortured while being held on suspicion of involvement in terrorism.
Now intelligence information relating to the allegations was released after three of the UK's highest-ranking judges dismissed Mr Miliband's appeal.
He had hoped to overturn an earlier court ruling that said summaries of information received by the British security services from United States intelligence should be disclosed.
The Court of Appeal decision was hailed by international media as a "resounding victory for freedom of speech".
But White House spokesman Ben LaBolt said the US was "deeply disappointed" with the judgment.
He said: "We shared this information in confidence and with certain expectations. As we warned, the court's judgment will complicate the confidentiality of our intelligence-sharing relationship with the UK, and it will have to factor into our decision-making going forward."
In Washington, a statement by the Office of the Director of National Intelligence, Dennis Blair, said the ruling was "not helpful".
It said: "The protection of confidential information is essential to strong, effective security and intelligence cooperation among allies.
"The decision by a United Kingdom court to release classified information provided by the US is not helpful, and we deeply regret it."
The ruling by the Lord Chief Justice Lord Judge, the Master of the Rolls Lord Neuberger and the President of the Queen's Bench Division Sir Anthony May related to publication of seven paragraphs which had to be redacted from High Court judgments already handed down.
One of the key paragraphs - released after yesterday's decision was announced - said that the reported treatment by the "United States authorities" of Mr Mohamed "could readily be contended to be at the very least cruel, inhuman and degrading".
Mr Miliband told MPs the ruling was leading to a "great deal of concern" in the US.
In a statement to the Commons, he said he had fought to prevent the release of the information to defend the "fundamental" principle that intelligence shared with the UK would be protected.
This "control principle" was essential to the relationship between the UK and the US.
Mr Miliband said he had spoken with US secretary of state Hillary Clinton about the case, which was being "followed carefully at the highest levels in the US system with a great deal of concern".
The treatment of Mr Mohamed went against British principles but was not carried out by the UK, he said.
The judgment was the latest ruling in long-running proceedings arising out of the case of British resident Mr Mohamed.
Mr Mohamed was detained in Pakistan in 2002 on suspicion of involvement in terrorism and then "rendered" to Morocco and Afghanistan. He was sent to Guantanamo Bay in 2004.
Now back in the UK, he is fighting to prove that British authorities helped to facilitate his detention and knew about his ill-treatment in Pakistan.
Lawyers for Mr Mohamed and the British and international media had argued that disclosure of the material was in the public interest.
They accused the Government of seeking to suppress "embarrassing and shaming" evidence of Britain's involvement in torture.
They said sensitive admissions by the CIA to the British security service over the ill-treatment of Mr Mohamed raised the prospect of both UK and US governments being exposed to "serious criminal liability for an international war crime".
Lawyers acting for the Foreign Secretary had accused the judges of "charging in" to a diplomatically sensitive area - jeopardising UK intelligence-sharing with the US.
In the lengthy ruling, the Lord Chief Justice said: "Nothing in this judgment should be seen as devaluing the confidentiality principle, and the understanding on which intelligence information is shared between this country and the USA."
He said the redacted paragraphs would not reveal information which would be of interest to a terrorist or criminal or provide "any potential material of value to a terrorist or a criminal".
Lord Judge said there was no secret about the treatment to which Mr Mohamed was subjected while in the control of the US authorities.
"We are no longer dealing with the allegations of torture and ill-treatment; they have been established in the judgment of the court, publicly revealed by the judicial processes within the USA itself," he said.
"If they contained genuinely secret material, the disclosure of which would of itself damage the national interest, my conclusion might be different."
He said Mr Mohamed was "taking civil proceedings for damages against the UK Government, in effect for their tortious involvement in the wrongdoing of the USA authorities".
After the ruling, Shami Chakrabarti, director of Liberty, said a public inquiry is now "inescapable".
Amnesty International backed the decision and joined calls for a new probe.
"The fact that Binyam Mohamed was tortured triggers the UK's human rights obligation, under domestic and international law, to investigate allegations of UK complicity in his abuse," said Amnesty's UK director Kate Allen.
Shadow foreign secretary William Hague said of the ruling: "It upholds the principles of intelligence-sharing between the US and UK and the need for justice and accountability in our democratic society.
"There is an urgent need to draw a line under this episode and restore British moral authority in the matter of allegations of complicity in torture."
Liberal Democrat foreign affairs spokesman Edward Davey said: "This is an embarrassing defeat for David Miliband and a victory for open government."Reuse content