By Brendan Pierson

(Reuters) - A federal judge ruled on Friday that the U.S. government must release photographs showing the treatment of detainees in U.S. custody at the Abu Ghraib prison in Iraq and other sites.

Judge Alvin Hellerstein in Manhattan ruled that his order would not take effect for 60 days to give the U.S. Department of Defense time to decide whether to appeal.

The order is a victory for the American Civil Liberties Union, which filed a lawsuit against the government in 2004 seeking the release of the photographs.

"The photos are crucial to the public record," ACLU deputy legal director Jameel Jaffer said in a news release. "They're the best evidence of what took place in the military's detention centers, and their disclosure would help the public better understand the implications of some of the Bush administration's policies."

The Department of Defense did not immediately return an email seeking comment.

Hellerstein ruled last August that the government had failed to show why releasing the photographs would endanger American soldiers and workers abroad, but gave the government a chance to submit more evidence. In Friday's order, however, he said additional evidence had failed to change his decision.

The photographs would be released in redacted form to conceal the identities of any individuals, according to court documents.

Former Senator Joe Lieberman of Connecticut said in 2009 that there were nearly 2,100 photographs, according to Hellerstein's August opinion.

Hellerstein also wrote in August that he had reviewed many of the photographs and that some were "relatively innocuous while others need more serious consideration."

A handful of images depicting abuse at Abu Ghraib emerged in 2004, prompting a public debate over whether the United States had tortured prisoners.

Hellerstein first ordered the government to turn over the photographs in 2005, but while that order was being appealed, Congress passed a law allowing the Secretary of Defense to withhold the photographs by certifying their release would endanger U.S. citizens.

The government has argued that the photographs are still shielded by that law, but Hellerstein rejected that argument last August and again on Friday. He said the Defense Secretary must review each photograph individually, and that the government has not proven that the Secretary did so.

(Reporting By Brendan Pierson and Joseph Ax in New York. Editing by Andre Grenon)