Some Guantanamo Bay detainees deemed not to pose a security threat could be released without first having access to civilian courts, a US Defence spokesman said.
Mr Larry Di Rita, chief spokesman for Defence Secretary Donald Rumsfeld, said no final decisions have been made about how the US government would respond to Supreme Court decisions this week requiring that detainees be given a way to challenge their incarceration.
But he said it was possible that if it could be determined some people need not be held then they also "need not necessarily be part of a judicial process".
Mr Di Rita referred to the Pentagon's new system of annually reviewing each of the nearly 600 detention cases at the US naval base at Guantanamo Bay in Cuba. Under that system, a panel of three military officers would assess each case, but the detainees would not be represented by lawyers.
"If there are people who can be released after some due process of review that we've established, it's worth considering whether that's the right next thing to do," Mr Di Rita said.
The Pentagon's annual reviews are to be overseen by Navy Secretary Gordon England, who said last week before the Supreme Court rulings that he expected the first review panel to meet within two weeks.
Most of the 595 detainees at Guantanamo were captured in the US war in Afghanistan in 2001 and most have been held without access to lawyers for more than two years. Human rights groups have complained the prisoners are in a legal limbo with little chance to gain their release.
The annual review programme was supposed to serve as the Pentagon's answer to those critics.
Earlier this week, the Pentagon announced that a five-member tribunal would try three suspects at Guantanamo. The military trial would be the first US war crimes tribunal since World War II.