* ACLU sharply critical of Obama decision
* White House likely to seek court order
* Obama defends decision (Adds more details, reaction throughout)
By Caren Bohan
WASHINGTON, May 13 (Reuters) - In a reversal, President Barack Obama said on Wednesday he would fight the release of dozens of photographs showing the abuse of terrorism suspects, over concern the images could ignite a backlash against U.S. troops.
The decision was a blow to some liberals in Obama's Democratic Party who see the photos as part of a broader effort to investigate Bush-era officials and cleanse America's image abroad.
Just last month the Obama administration had said it would comply with a court order to release the pictures by May 28, saying legal options for appealing the case had been limited.
But Obama shifted gears after senior military commanders and some members of Congress expressed misgivings about the potential for the photos to generate violence against U.S. troops in Iraq and Afghanistan.
Obama defended his decision, saying publication of the photographs "would not add any additional benefit to our understanding of what was carried out in the past by a small number of individuals."
"In fact, the most direct consequence of releasing them, I believe, would be to further inflame anti-American opinion and to put our troops in greater danger," Obama told reporters. "Moreover, I fear the publication of these photos may only have a chilling effect on future investigations of detainee abuse."
White House spokesman Robert Gibbs said the administration is likely to seek a court order aiming at blocking the release of the photos, which had been expected within weeks.
Gibbs was peppered with questions about Obama's shift in course. He said Obama, who has seen some of the pictures, told his legal team last week that he did not feel comfortable with releasing them.
'MAKES A MOCKERY'
The American Civil Liberties Union, which argued for the photos' release, expressed outrage and said the decision "makes a mockery" of Obama's campaign promise of transparency.
"It's absolutely essential that these photos be released so the public can examine for itself the torture and abuse that was conducted in its name, and so that high-level officials who authorized or permitted that abuse can be held accountable," ACLU attorney Amrit Singh said.
The human rights group Amnesty International said it was disappointed.
"Human beings have been tortured and denied basic rights. The American people have been lied to, and government officials who authorized and justified abusive policies have been given a pass," said the group's executive director, Larry Cox. He said the full story had not been told.
But the shift was welcomed by Sen. Lindsey Graham, a Republican, and Sen. Joe Lieberman, an independent, who said Obama "did exactly the right thing."
"The fact that the president reconsidered the decision is a strength not a weakness," they said in a statement.
Defense Secretary Robert Gates said he had had second thoughts about the decision to release the pictures after hearing the concerns of the top U.S. commanders in Afghanistan and Iraq, U.S. Army Generals David McKiernan and Ray Odierno.
"Our commanders, both General McKiernan and General Odierno, have expressed very serious reservations about this, and their very great worry that release of these photographs will cost American lives," Gates told U.S. lawmakers.
"That was all it took for me."
Obama inflamed partisan tensions in Washington in April by releasing memos written by Bush-era Justice Department lawyers that provided the legal justification for harsh interrogation tactics such as waterboarding, which is simulated drowning.
On Capitol Hill on Wednesday, the first of what could be a series of hearings about the topic was held. A former FBI agent, Ali Soufan, argued that methods like waterboarding produced unreliable evidence and were ineffective.
Former Vice President Dick Cheney has argued that the tactics did provide valuable intelligence and has appealed to the Obama administration to release memos that detail the methods' effectiveness.
Some Democrats, such as House of Representatives Speaker Nancy Pelosi, have been calling for appointment of a "truth commission" to conduct a public probe into Bush administration interrogation tactics.