In a sharp reversal, President Obama announced Wednesday that he will not release hundreds of photos potentially showing U.S. military personnel abusing prisoners in Iraq and Afghanistan in the aftermath of the Sept. 11, 2001, terrorist attacks.

"My belief is the publication of these photos would not add any additional benefits to our understanding of what was carried out in the past by a small number of individuals," Obama said in a brief appearance. "The most direct consequence would be to further inflame anti-American opinion and put our troops in greater danger."

Obama added that he's made it clear to military officials, however, that the abuse of detainees is "prohibited and will not be tolerated."

Obama told his legal advisers last week that he did not feel comfortable with the release of the photos because he believes they would endanger U.S. troops, and that the national security implications of such a release have not been fully presented in federal court, a senior administration official told FOX News.

The Pentagon had planned to release the photos by May 28 in response to a Freedom of Information Act lawsuit filed by the American Civil Liberties Union. That decision was made after the Justice Department lost its latest round in federal court and concluded that any further appeal probably would be fruitless.

But on Tuesday, the president raised the issue of these photos with Gen. Ray Odierno, the top U.S. commander in Iraq, during a White House meeting and told him of his decision to argue against this release, the official said.

Pentagon spokesman Geoff Morrell said Wednesday that Odierno was the most vocal opponent of releasing the photos and that he shared his concerns with Defense Secretary Robert Gates.

"Odierno was really the one who persuaded the secretary that this had to be fought and the secretary completely agreed," Morrell said.

Gates, in turn, vocalized the concerns to Obama in a series of discussions over the past weeks, Morrell said.

The belief of most of the commanders overseas was the potential the photos had to "incite violence and serve as a potential recruiting tool for terrorists" was too big to let happen without more of a fight.

The ACLU, which has claimed the release of the photos will help the American people decide whether the abuse was widespread, immediately criticized the decision.

"The Obama administration's adoption of the stonewalling tactics and opaque policies of the Bush administration flies in the face of the president's stated desire to restore the rule of law, to revive our moral standing in the world and to lead a transparent government," Anthony D. Romero, executive director of the ACLU, said in a statement.

"If the Obama administration continues down this path, it will betray not only its promises to the American people, but its commitment to this nation's most fundamental principles," he continued. "President Obama has said we should turn the page, but we cannot do that until we fully learn how this nation veered down the path of criminality and immorality, who allowed that to happen and whose lives were mutilated as a result.

"Releasing these photos -- as painful as it might be -- is a critical step toward that accounting," he added. "The American people deserve no less."

White House spokesman Robert Gibbs said Wednesday that the president believes releasing the photos would only "sensationalize" rather than "illuminate" the investigation into detainee abuse.

Republican leaders praised Obama's decision.

"I agree with the president that the release of these photos would serve no purpose other than put our troops in greater danger," he said in a statement. "The president made the right decision and I applaud him for it."

House Minority Leader John Boehner, R-Ohio, told FOX News he believes Obama made the right move.

"I think the release of these photos would do nothing more than give our enemies a recruiting tool that would put our soldiers in danger and frankly put Americans in danger," he said.

Some lawmakers had urged Obama to fight the release of the photos because they feared it would turn into a sequel to the Abu Ghraib prison scandal in Iraq, which caused an international backlash against the U.S. with photos in 2004 of smirking U.S. soldiers posing with detainees, some naked, being held on leashes or in painful positions.

Nine U.S. soldiers were eventually found guilty in the Abu Ghraib abuse case.

Whether the new photos are as repugnant as those from Abu Ghraib is still an open question. But one U.S. official told FOX News that hundreds of photos are involved, drawn from military investigations into alleged abuse between 2001 and 2005.

A senior Pentagon official told FOX News that the government will shift its defense to arguing the negative national security implications that the release of the photos will have.

This legal approach was not employed from the start, the official said, because it was working poorly in the original case that challenged the release of the Abu Ghraib photos. That case was dropped because the photos were all leaked.

FOX News' Major Garrett, Catherine Herridge, Justin Fishel, Steve Centanni and The Associated Press contributed to this report.