The political battle over the fate of the detainees at Gunatanamo Bay just got more contentious.

The Obama administration is considering an executive order to indefinitely imprison a small number of Guantanamo Bay detainees, a move that would be in line with Bush administration policy but already has drawn scorn from civil liberties groups.

"This is not change -- this is more of the same," Anthony D. Romero, executive director of the American Civil Liberties Union, said in response to reports that surfaced Friday of the possible executive order. "If President Obama issues an executive order authorizing indefinite detention, he'll be repeating the same mistakes of George Bush, and his policies will be destined to fail as were his predecessor's."

He added, "Throwing people into prison without charge, conviction or providing them with a trial is about as un-American as you can get."

But former top Bush adviser Karl Rove said the news should be welcomed.

"We are, after all, in a war -- not an overseas contingency operations as some in the administration have suggested is the new title for it," he told FOX News. "And in a war, you take the people you sweep up on the battlefield and you hold them until the war is over or until they no longer represent a threat."

The White House is weighing the move out of concern that Congress might otherwise stymie its plans to quickly close the naval prison in Cuba.

Under the proposal, detainees considered too dangerous to prosecute or release would be kept in confinement in the U.S. or possibly overseas, two administration officials told the Associated Press on Friday. Otherwise, the White House could get bogged down for months seeking an agreement with Congress on a new legal detention system.

But that hasn't allayed the concerns of critics of the proposal.

"Prolonged imprisonment without trial is exactly the Guantanamo system that the president promised to shut down," Shayana Kadidal, a lawyer for the Center for Constitutional Rights, said in a written statement Friday.

He added: "If the last eight years have taught us anything, it's that executive overreach, left to continue unchecked for many years, has a tendency to harden into precedent."

No final decisions have been made about the order, which would be the fourth major mandate by President Obama to deal with how the United States treats and prosecutes terror suspects and foreign fighters.

One of the officials said the order, if issued, would not take effect until after the Oct. 1 start of the 2010 budget year. Already, Congress has blocked the administration from spending any money this year to imprison the detainees in the United States -- which in turn could slow or even halt Obama's pledge to close the prison by Jan. 21.

The administration also is considering asking Congress to pass new laws that would allow the indefinite detentions, the official said.

Both the officials spoke Friday to the Associated Press on condition of anonymity because they were not authorized to discuss the still-tentative issue publicly. The possibility of an executive order was first reported by the investigative group ProPublica and The Washington Post.

Without legislative backing, an executive order is the only route Obama has to get the needed authority.

In a statement Friday night, Senate Republican leader Mitch McConnell of Kentucky cast doubt that Congress would approve funding for transferring or imprisoning detainees in the U.S. without detailed plans on how it would work.

Lawmakers this month blocked $80 million the administration had requested for transferring the detainees. Without the money, Obama's order can't be carried out.

"Bipartisan majorities of Congress and the American people oppose closing Guantanamo without a plan, and several important questions remain unanswered," McConnell said. He said Obama demanded the transfers "before the administration even has a place to put the detainees who are housed there, any plan for military commissions, or any articulated plan for indefinite detention."

Obama's order would apply only to current detainees at Guantanamo.

There are 229 detainees currently being held at Guantanamo. Obama said last month he was looking at continued imprisonment for a small number of Guantanamo detainees whom he described as too dangerous to release. He called it "the toughest issue we will face."

It's not clear how many detainees could fall into that category. Defense and Justice Department officials have privately said at least some could be freed at trial because prosecutors would be reluctant to expose classified evidence against the detainees. Some of that evidence also might be thrown out because of how it was obtained -- potentially by cruel, inhuman or degrading treatment.

The Associated Press contributed to this report.