WASHINGTON  The Supreme Court on Monday vacated a lower court ruling that would have required the government to release photographs showing the abuse of prisoners in Iraq and Afghanistan.

The decision was three sentences long and unsigned, and it followed the enactment of a law in October allowing the secretary of defense to block the pictures’ release. The Supreme Court sent the case back to the lower court, the United States Court of Appeals for the Second Circuit, in New York, for further consideration in light of the new law.

The case was brought by the American Civil Liberties Union under the Freedom of Information Act, which makes disclosure of information in the hands of the executive branch mandatory unless an exemption applies. The Second Circuit ordered the photos released last year, and the Justice Department initially recommended against an appeal to the Supreme Court.

But President Obama overruled his lawyers, saying his national security advisers had persuaded him that releasing the photos would inflame anti-American sentiment abroad and endanger American troops. Some of the pictures, according to a government brief, showed “soldiers pointing pistols or rifles at the heads of hooded and handcuffed detainees,” a soldier who appears to be striking a detainee with the butt of a rifle, and a soldier holding a broom “as if sticking its end” into a prisoner’s rectum.