The United States is said to be planning to release 140 of the 660 prisoners at its Guantanamo Bay, Cuba, prison for suspects in the US-declared war on terrorism.
A US military official told Timemagazine "the easiest 20 per cent" of detainees would be released. It did not identify its source, who said the military was waiting for "a politically propitious time to release them".
Human rights groups have criticised the United States for holding the detainees without charges. The US Supreme Court - in a case involving two Britons, two Australians and 12 Kuwaitis - has agreed to decide if foreign nationals can use US courts to challenge their detention at the base.
According to Time, activities leading toward release of the 140 prisoners have accelerated since the Supreme Court agreed to hear the case. It said US officials had concluded some detainees were kidnapped for reward money offered for al-Qaeda and Taliban fighters.
No charges have been filed against any of the 660 prisoners at the US Navy base in Cuba. Defence officials say many are suspected of being members of Osama bin Laden's al-Qaeda network or Taliban fighters from the war in Afghanistan.
Separately on Sunday, a British human rights lobbyist said five European nations were close to a deal to repatriate citizens held by the United States in Guantanamo Bay, possibly as soon as Christmas.
Stephen Jakobi, director of Fair Trials Abroad, said his group had been tracking talks over the prisoners between Washington and Britain, France, Denmark, Sweden and Spain.
Since the prison opened in January 2002, prisoners from 42 countries have been taken to Guantanamo Bay for detention and questioning. As of November 24, a total of 84 prisoners had been transferred to their home countries for release and four were returned to Saudi Arabia for imprisonment.