WASHINGTON - President Obama decided not to release detainee abuse photos from Iraq and Afghanistan after Prime Minister Nouri al-Maliki warned that Iraq would erupt into violence and that Iraqis would demand that U.S. troops withdraw from Iraq a year earlier than planned, two U.S. military officers, a senior defense official, and a State Department official told McClatchy Newspapers.

In the days leading up to a May 28 deadline to release the photos in response to an American Civil Liberties Union lawsuit, U.S. officials, led by Christopher Hill, the U.S. ambassador to Iraq, told Maliki the administration was preparing to release photos of suspected detainee abuse taken from 2003 to 2006.

When U.S. officials told him, "he went pale in the face," said a U.S. military official, who along with others requested anonymity because of the matter's sensitivity.

The official said that releasing the photos would lead to more violence that could delay the scheduled U.S. withdrawal from cities by June 30, and that Iraqis would not distinguish between old and new photos. The public outrage and increase in violence could lead Iraqis to demand a referendum on the U.S.-Iraqi security agreement and refuse to permit U.S. forces to stay until the end of 2011.

Maliki said "Baghdad will burn" if the photos are released, said a second U.S. military official.

A U.S. official knowledgeable about the photos said at least two of them depict nudity; one is of a woman suggestively holding a broomstick; one shows a detainee with bruises but offers no explanation of how he got them; and another is of hooded detainees with weapons pointed at their heads.

Some of the photos were of detainees in prisons, while others were taken at the time a detainee was captured.

Iraq is scheduled to hold a referendum by July 30 on the security accord, which calls for the withdrawal of all U.S. troops by the end of 2011.

If the accord were rejected, the United States would have to withdraw from Iraq within a year of the vote or by summer 2010. Some U.S. officials fear that would be before Iraq's security forces are ready to protect the country on their own.

The accord calls for the United States to train Iraqi forces in specialized areas such as aviation and intelligence-gathering and to step to the side as Iraqi forces take control of their communities.

Maliki's office, Iraq's deputy prime minister, and the foreign minister did not answer calls seeking comment.

Denis McDonough, the deputy U.S. national security adviser for strategic communications, said Obama "has been clear that releasing the photos would have no benefit except to potentially increase the risk to our troops."

The administration, which as late as April had agreed to release as many as 2,100 photos, said in the two weeks before the deadline neared that the release could trigger a backlash against U.S. troops.

The photos are part of a 2004 lawsuit that sought the release of photos that were part of investigations of detainee abuse at Abu Ghraib and a half-dozen other prisons. The Pentagon objected to the release, but the U.S. Court of Appeals for the Second Circuit upheld a lower-court ruling to release them.

Yesterday, the ACLU released a letter signed by a dozen organizations calling for the release of the photos.