The Pentagon has freed the last three of 22 Chinese Uighurs from the detention camp at Guantanamo Bay, Cuba.

Announcing the release of Yusef Abbas, Saidullah Khalik and Hajiakbar Abdul Ghuper, Pentagon spokesman Rear Adm. John Kirby today called it a "significant milestone" in efforts to close the prison.

The Pentagon has transferred the three to Slovakia, which it thanked for taking them. A U.S. District Court ordered their release in 2008, and the executive branch has since been seeking countries to take them, fearing they would be persecuted if returned to China, where Uighurs are a Muslim minority in the Western part of the country.

In 2002, the United States designated the East Turkestan Islamic Movement, a Muslim separatist group in western China, as a terrorist organization.

Slovakia becomes the sixth country to resettle Uighurs freed from Guantanamo, joining Switzerland, El Salvador, Bermuda, Palau, and Albania, the Pentagon said.

After the transfer, 155 detainees remain at Guantanamo.

Promised by President Obama during his 2008 presidential campaign and ordered two days after his swearing in as president, closing the Guantanamo Bay prison has proven difficult and complicated.

Congress recently made things a bit easier. Obama signed into law a new National Defense Authorization Act last week that eased restrictions on detainee transfers, calling it a "positive step" toward Guantanamo's closure.

The law still bans the transfer of any Guantanamo detainees to the continental United States.