Leading human rights groups Thursday called on the U.S. government to account for terrorism suspects they believe were detained by U.S. authorities abroad but whose whereabouts are now unknown. The Bush administration has said it maintained secret overseas detention sites but emptied them last year. VOA's David Gollust reports from the State Department.

In an unusual joint action, six human rights groups including Amnesty International and Human Rights Watch have published a list of 39 terrorism suspects they believe were secretly detained by the United States at one time or another but cannot be accounted for now.

A 21-page report by the rights organizations says the so-called ghost detainees include nationals from several countries including Pakistan, Egypt, Libya and Kenya who were detained in anti-terrorism operations since 2001, and held at least for some time in secret U.S. detention sites.

President Bush acknowledged the existence of secret CIA detention sites abroad in an address last September, but said that the 14 prisoners in them at the time had been transferred to the Guantanamo Bay detention facility.

News reports last year quoted U.S. intelligence officials as saying the secret sites may have held nearly 100 prisoners in the months before the President's disclosure.

The six human rights groups called on the Bush administration to account for the other prisoners, whose cases they said they were able to document from government disclosures and interviews with released detainees, witnesses and relatives.

In a talk with VOA, Joanne Mariner, Terrorism and Counter-terrorism Coordinator at Human Rights Watch, said the prisoners may have been sent back to their countries of origin or elsewhere for continued detention, and possible mistreatment: "It's possible they were transferred to their home countries, which in the case of several of them is of real concern because their home countries are places like Libya, Egypt and Morocco, places in which the torture of terrorism suspects is commonplace. And we're certainly afraid that they may continue to be held in secret detention in these countries and face abuse there," she said.

In connection with the report, three of the groups including Amnesty International filed a federal lawsuit under the U.S. Freedom of Information Act seeking disclosure of documents and other information on the ghost detainees.

Amnesty Deputy Executive Director Kurt Goering said in a VOA interview the decision to take the issue to the courts came because the CIA, Justice Department and other agencies were unresponsive to information requests made through regular channels. "We've been essentially stonewalled. None of the agencies, the five agencies, have delivered or provided any significant information in response to these requests. The CIA has stonewalled completely, there's been absolutely no response. And so in accordance with the Freedom of Information Act regulations, we are through this lawsuit charging that the U.S. government is violating its own laws," he said.

Both Goering of Amnesty and Mariner of Human Rights Watch said the President's September statement did not preclude the future use of secret detention sites overseas, and that there are reports the practice continues.

At a news briefing however, State Department Deputy Spokesman Tom Casey said there was no reason to believe that the situation has changed since the September speech, suggesting that there were no new secret detainees.

Casey also insisted the detainee issue has not undermined the United States' moral authority to speak out on human rights issues in other countries.

"We recognize that the United States, in our own country, does not always have perfect record and historically has not always done so. That does not lessen the fact that the United States has been and continues to be the world's leading advocate for human rights around the world, and it's a cause that we believe in, that is part of the values of our country and one that we are going to continue to speak about," he said.

In a speech in The Hague late Wednesday, State Department Legal Adviser John Bellinger said the issue of terrorist detainees posed an unprecedented legal challenge for the Bush administration, which he said has not ignored, changed or reinterpreted international law.