The prisoners there "are held without due process and in total violation of the norms and standards of international humanitarian and human rights law," a statement issued by the Council's Central Committee declared.
The statement was supported by the US National Council of Churches (NCC), which links 36 Protestant, Orthodox and Afro-American communities across the country and has been campaigning for the detainees to be granted due legal process.
Bush is a fervent Christian, and the backing of evangelical Christians in several key states helped secure his re-election last November.
The Council statement, issued after a session of its steering Central Committee, also called on the administration to allow the NCC to visit the detainees - many held since the end of 2001 as part of the administration's "war on terror." It also called on all NCC churches to educate their congregations on the situation of those held at the base and to urge believers to call "for the release of those being held in detention under inhuman conditions."