The State Department confirmed Tuesday the United States is holding talks with a number of Muslim countries on the return of their nationals now held at the U.S. detention center at the Guantanamo Bay naval base in Cuba. The aim of the talks is to reduce the number of prisoners held at the controversial facility to a relative few.

The United States reached a prisoner-transfer agreement with Afghanistan last week, and officials here say talks are under way with several other Muslim countries in an effort to sharply reduce the prisoner population at Guantanamo.

The detention center was opened in 2002 as the central holding point for people detained in the U.S. global war on terrorism.

A frequent target of criticism from human rights groups, it still holds about 510 prisoners, many of them al-Qaida and Taleban suspects captured in the U.S.-led invasion of Afghanistan.

The Washington Post reported Tuesday the Bush administration is nearing transfer agreements with ten Muslim countries including Saudi Arabia and Yemen, which along with Afghanistan have the largest numbers of nationals held at Guantanamo.

It said U.S. officials are also trying to persuade a European country to accept 15 Chinese Uighur and two Uzbek detainees ready to be released, but who will not be returned to their home countries for fear of abuse and torture.

Adam Ereli

At a news briefing, Deputy State Department Spokesman Adam Ereli said understandings were being negotiated with a number of Muslim governments, which would assume responsibility for detainees including continued detention or prosecution if needed, while also assuring they will be treated humanely and consistent with international standards.

Spokesman Ereli would not confirm an assertion by the Washington Post that the aim is to reduce the Guantanamo population to a hard-core of about 100 prisoners. But he did say some would remain under indefinite detention.

"Without getting into specific numbers because I don't think frankly we've reached that degree of specificity, it is accurate to say that there are going to be a number of detainees in Guantanamo who are not eligible for transfer," said Mr. Ereli.  "And this is what we would [call], you know, the worst of the worst, those that continue to pose such a threat to the international community that their continued detention in Guantanamo is necessary."

The United States has to date transferred about 70 Guantanamo detainees to the custody of their home countries and given about 200 others their outright release.

Mr. Ereli acknowledged that a small number of those transferred or released thus far have returned to terrorist activity.

He said the issue has figured in the talks with recipient governments, who he said should have the logistical capability to handle prisoners of that nature.

The private monitoring group Human Rights Watch welcomed the U.S. effort to return detainees, though it said it was concerned about whether the United States can get credible assurances of humane treatment from countries like Egypt and Saudi Arabia, where it said torture is routinely practiced.

A Human Rights Watch spokesman said seeking third-country refuge for the Chinese Uighur and Uzbek prisoners was commendable. But he suggested it should also be done for Saudis and others who should either go to other countries or be allowed to stay in the United States.