The US has released 20 prisoners -- and added another 20 -- at its Guantanamo Bay military prison for suspects in the US-declared war on terrorism, the Pentagon said on Monday.
After the 20 prisoners were sent from Guantanamo on Friday to their home countries, the US military on Sunday brought 20 new suspects to the naval base jail, which still holds about 660 detainees, the announcement said.
"Senior leadership of the Department of Defense, in consultation with other senior US government officials, determined that these [20 released] detainees either no longer posed a threat to US security or no longer required detention by the US," the Pentagon said in a brief statement.
No charges have been filed against any of the 660 prisoners at the US Navy base in Cuba. Defense officials say many are suspected of being members of Osama bin Laden's al-Qaeda network or Taliban fighters from the war in Afghanistan.
Human rights groups have criticized Washington for holding the detainees for a long period without charge.
The US Supreme Court, in a case involving two British, two Australian and 12 Kuwaiti detainees, agreed earlier this month to decide if foreign nationals could use American courts to challenge their incarceration at the base in Cuba.
Defense officials refused to identify those released on Friday or provide information about the new prisoners.