The American Civil Liberties Union says it will continue to fight for the release of photographs of foreign detainees being abused by their U.S. captors, after Defense Secretary Robert Gates invoked new powers to block them from public view.

ACLU spokesman Jameel Jaffer says the photos are "an important part of the historical record." And he says preventing their release "sets a bad precedent for the government to be suppressing information that relates to government misconduct."

The ACLU sued for release of the 21 photos showing prisoner abuse in Afghanistan and Iraq. Federal courts had rejected the government's arguments to keep them from public view, so Congress gave Gates new power to keep them private.

Gates argues disclosing the photos publicly would endanger U.S. citizens and troops deployed abroad.