FACTBOX-U.S. Supreme Court case on Guantanamo prison

(Reuters) - The U.S. Supreme Court hears arguments on Wednesday in a major case to decide the legal rights of terror suspects held in the U.S. detention center at Guantanamo Bay, Cuba. Following are some facts about the case.

* The Guantanamo prison opened in January 2002 to house prisoners swept up in the U.S.-led invasion of Afghanistan and elsewhere. About 305 detainees are in the camp, according to the Defense Department, and about 470 have been released.

Among the 14 designated "high-value" detainees are suspected September 11 attack organizer Khalid Sheikh Mohammed.

* The court will consider the constitutionality of the 2006 Military Commissions Act denying Guantanamo inmates "habeas corpus" rights to seek a judicial review of their detention.

* Some inmates, human-rights groups and federal law-enforcement officials have described abusive interrogation and treatment at the prison. The Defense Department says it treats the inmates humanely, while collecting intelligence in the battle against terrorism.

* Among those who have filed briefs with the Supreme Court on the side of Guantanamo inmates are the U.N. High Commissioner for Human Rights, a group of retired U.S. military officers, a group of former federal judges, the American Bar Association, European and British parliament members, Amnesty International and Republican U.S. Sen. Arlen Specter.

* Groups supporting the government's position with briefs include retired U.S. generals and admirals, the Committee on the Present Danger and the American Center for Law and Justice.

* The Supreme Court has twice previously ruled against the government's procedures for holding or trying detainees at Guantanamo. A federal appeals court upheld the 2006 law, but in a highly unusual move, a majority of Supreme Court justices voted to take the case after earlier rejecting a petition to hear it.

(Reporting by Randall Mikkelsen; Editing by David Alexander and Todd Eastham)