WASHINGTON - President Obama said Wednesday that his administration was trying to figure out what to do with detainees at the military prison at Guantanamo Bay, Cuba, who cannot be prosecuted but are too dangerous to be released.

Earlier in the day, the White House acknowledged that administration officials were drafting an executive order to set up a review process for detainees held indefinitely at Guantanamo.

Such an order would be further acknowledgment by Obama that his campaign pledge to close the prison will remain unfulfilled for now. The president has long said that some terrorist suspects would be held indefinitely, but he has hoped for that to be on U.S. soil.

During a news conference touting end-of-the-year legislative victories, Obama showed little interest in discussing the island prison.

Without discussing details of the proposed executive order, which has not been sent to him, Obama said that some detainees could not be prosecuted because evidence against them was tainted during their apprehension or detention before they were moved to Guantanamo.

Some were subjected to harsh interrogation tactics, including waterboarding, a simulated drowning technique.

Still, Obama said that some of the detainees were simply too dangerous to be released.

"When I get that report, I'm sure that I'll have more comments on it," Obama said. "Striking this balance between our security and making sure we are consistent with our values and our Constitution is not an easy task."

Creating a system of reviews, including providing lawyers for detainees who want to challenge their detention, will ultimately show the world "we stand for something beyond just our economic power or our military might, but we have these core ideals. . . . That's one of our most powerful weapons."

White House spokesman Robert Gibbs said earlier in the day that the executive order is in line with procedures Obama broadly described in a May 2009 speech about detainees who would be held indefinitely at that military prison.

"We must have clear, defensible, and lawful standards for those who fall in this category," Obama said at the time. "We must have fair procedures so that we don't make mistakes. We must have a thorough process of periodic review, so that any prolonged detention is carefully evaluated and justified."

The draft was first reported Tuesday night in a story posted online by the Washington Post.

By setting up a review process for detainees at Guantanamo by executive order, the president could make indefinite detention somewhat more palatable to liberal voters who adamantly oppose it. An executive order also would allow Obama to avoid Congress, which has shown increasing reluctance to follow his lead on Guantanamo issues.

The House and Senate have approved legislation that would bar Guantanamo detainees from being brought to the United States for trial.