Citing intelligence, defence and diplomatic officials, the newspaper said on Sunday that the Pentagon and the CIA had asked the White House to decide on a more permanent approach for those it would not set free or turn over to courts at home or abroad.
The Defence Department - which holds at least 500 prisoners in Guantanamo Bay - plans to ask the US Congress for $25 million to build a 200-bed prison to hold detainees who are unlikely to ever go through a military tribunal for lack of evidence, defence officials told the newspaper.
The new prison, dubbed Camp 6, would be designed for prisoners the government believes have no more intelligence to share, the newspaper reported.
"Since global war on terror is a long-term effort, it makes sense for us to be looking at solutions for long-term problems," Bryan Whitman, a Pentagon spokesman, was quoted as saying.
"This has been evolutionary, but we are at a point in time where we have to say: 'How do you deal with them in the long term?'"
The paper said the outcome of a review under way would also affect those expected to be captured in the course of future counterterrorism operations.
One proposal would transfer large numbers of Afghan, Saudi and Yemeni detainees from the US military's Guantanamo Bay, Cuba, detention centre into new US-built prisons in their home countries, it said.