Rice's spokesman, Sean McCormack, told reporters that the secretary of state made the assurance to visiting German Foreign Minister Frank- Walter Steinmeier.
McCormack did not say whether Rice discussed specifics of the secret prison reports, which are likely to come up during her five-day trip to Europe next week.
Earlier, CIA Director Porter Goss denied the agency tortures terrorism suspects -- as did U.S. President George W. Bush in an address to reporters in Texas.
"The United States of America does not torture, and that is important for people around the world to understand," Bush said.
Yesterday, a senior EU official said that the bloc could revoke the voting rights of any European Union country found to have housed such facilities. Their existence was first alleged in a report in "The Washington Post" earlier this month.
(AFP/ABC)