WASHINGTON — U.S. officials say the Pentagon’s long-awaited plan to shut down the detention center at Guantanamo Bay, Cuba, and transfer the remaining detainees to a facility in the United States calls for up to $475 million in construction costs that would ultimately be offset by as much as $180 million per year in operating cost savings.

The plan, which will be delivered to Congress today, is the administration’s last-ditch effort to make good on President Barack Obama’s campaign vow to close Guantanamo and convince lawmakers to allow the Defense Department to move nearly 60 detainees to the U.S. But the plan provides few details, and may only further antagonize members of Congress who have repeatedly passed legislation banning any effort to move detainees to the U.S.

Rep. Mac Thornberry, R-Texas, chairman of House Armed Services Committee, has said his panel would hold a hearing on a closing plan. But he sent a letter to Obama warning that Congress has made clear what details must be included in any plan and that anything less than that would be unacceptable.

Obama, meanwhile, planned to make a midmorning statement on Guantanamo at the White House.

U.S. officials say the plan considers 13 different locations in the U.S., including seven existing prison facilities in Colorado, South Carolina and Kansas, as well as six other locations on current military bases. They say the plan doesn’t recommend a preferred site and the cost estimates are meant to provide a starting point for a conversation with Congress.

More detailed spending figures, which are considered classified, will be provided to Congress, said the officials, who were not authorized to discuss the plan publicly ahead of its release, so spoke on condition of anonymity.

The seven facilities reviewed by a Pentagon assessment team last year were: the U.S. Disciplinary Barracks and Midwest Joint Regional Corrections Facility at Leavenworth, Kansas; the Consolidated Naval Brig, Charleston, South Carolina; the Federal Correctional Complex, which includes the medium, maximum and supermax facilities in Florence, Colorado; and the Colorado State Penitentiary II in Canon City, Colorado, also known as the Centennial Correctional Facility.

According to the officials, the U.S. facilities would cost between $265 million and $305 million to operate each year. The annual operating cost for Guantanamo is $445 million, but the officials said the Cuba detention center will need about $225 million in repairs and construction costs if it continues to be used.

They said it will cost between $290 million and $475 million for construction at the various U.S. sites, depending on the location. Some of the more expensive sites are on the military bases, which would need more construction. Because of the annual operating savings, the officials said the U.S. would make up the initial construction costs in three to five years.

Late last year, other U.S. officials said that the assessments done by the Pentagon team suggested that the Centennial Correctional Facility in Colorado is a more suitable site to send detainees whom officials believe should never be released. Those officials were not authorized to discuss that matter publicly, so spoke on condition of anonymity.

Members of Congress have been demanding the Guantanamo plan for months, and those representing South Carolina, Kansas and Colorado have voiced opposition to housing the detainees in their states.

The administration is currently prohibited by law from moving Guantanamo Bay detainees to the United States.

The long-running dispute has taken on added intensity now because the White House has launched a final push to close to the prison before Obama leaves office. Advocates of closing Guantanamo say the prison has long been a recruiting tool for militant groups and that holding extremists suspected of violent acts indefinitely without charges or trial sparks anger and dismay among U.S. allies.

Opponents, however, say that changing the detention center’s ZIP code won’t solve those problems. And they warn that moving al- Qaida-linked detainees to the U.S. could create security concerns around the new location.

There are currently 91 detainees at Guantanamo Bay. Of those, 35 are expected to be transferred out by this summer.

The rest are either facing trial by military commission or have been determined to be too dangerous to release but are not facing charges. Some can’t be charged because of insufficient evidence and some may face future prosecution or have been designated for indefinite detention under the international laws of war.

Seven detainees are in the early stages of trial by military commission, including the five men accused of planning and aiding the Sept. 11 terrorist attack, and three have been convicted and are serving sentences.

At its peak in 2003, Guantanamo held nearly 680 detainees, and there were about 245 when Obama took office.

“We’ve always been very clear about what needs to happen,” said Navy Capt. Jeff Davis, a Pentagon spokesman. “We’re going to continue to transfer detainees to other countries who agree to take them, and take steps to make sure that … the threat they pose to the U.S. is limited. Second, that we’ll continue to prosecute those that can be prosecuted. And third, that there’s this small group of individuals that can neither be safely transferred nor prosecuted, and it will address those three things and lay out a range of options.”

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