LONDON — In an embarrassing reversal, Britain confirmed yesterday that one of its remote outposts — the Indian Ocean island of Diego Garcia — had twice been used by America as a refueling stop for the secret transfer of two terrorism suspects.

The CIA acknowledged that previous data given to America’s strongest ally “turned out to be wrong.” Foreign Secretary David Miliband of Britain told Parliament that recent talks with Secretary of State Rice showed two suspects had been on flights to Guantanamo Bay and Morocco in 2002 that stopped on Diego Garcia, an American base on British soil.

Prime Minister Blair came under heavy criticism for Britain’s close alliance with America in the war in Iraq and its part in the American-led war on terrorism. The latest disclosure could pressure America to identify other countries used in extraordinary renditions, a practice of transferring suspects without formal extradition proceedings that human-rights groups say opens the door for third-party countries to torture suspects.

Mr. Miliband told lawmakers he was “very sorry” to have to correct statements made by the government in 2005, 2006, and 2007 that there were no such transfers involving Britain.

He and Ms. Rice “both agree that the mistake made in these two cases are not acceptable, and she shares my deep regret that this information has only just come to light,” said Mr. Miliband, who has sometimes broken ranks with the British government over military action in Iraq and policies in the Middle East.

The CIA acknowledged that the information previously provided to the British “turned out to be wrong,” despite earlier America’s assurances that none of the secret flights since the September 11, 2001, attacks had used British airspace or soil.

The agency, which said that neither of the two suspects was tortured or held on Diego Garcia, reviewed rendition records late last year and discovered that in 2002 the CIA had refueled two separate planes.

“The refueling, conducted more than five years ago, lasted just a short time. But it happened. That we found this mistake ourselves, and that we brought it to the attention of the British government, in no way changes or excuses the reality that we were in the wrong,” CIA Director Michael Hayden said in a message obtained by the Associated Press.

Despite American assurances, British officials kept pressure on their American counterparts to check all records of rendition flights, according to a British government official who spoke on condition of anonymity because of the sensitivity of the issue.

“We consistently sought reassurances because of the high public and parliamentary interest in this issue,” the official told the AP, saying it was not clear what prompted the American investigation. Washington disclosed that two flights — one bound for the American prison camp at Guantanamo Bay, Cuba, and one bound for Morocco, stopped at Diego Garcia, which Britain leased to the Americans in the 1960s.

It is unclear why Diego Garcia was used as a refueling point.

The British atoll is in the heart of the Indian Ocean and largely cut off to outsiders or civilians. Although it is a British territory, the American base is controlled by Americans and requests to visit the territory are handled by the American government.