The United States must release photographs showing abuse of detainees in Iraq and Afghanistan, a judge has ruled in a long-running clash over letting the world see the potentially disturbing images.

US District Judge Alvin Hellerstein’s ruling on Friday gives the government, which has fought the case for more than a decade, two months to appeal before the photos are released.

The American Civil Liberties Union has been seeking to make them public in the name of government accountability.

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The Defense Department is studying the ruling and will make any further responses in court, spokesman Lieutenant Colonel Myles Caggins III said.

The ACLU has said the pictures “are manifestly important to an ongoing national debate”.

The fight over the photographs reaches back to the early years of the wars in Iraq and Afghanistan, and invokes the images of abuse at Abu Ghraib prison in Iraq that sparked international outrage after they emerged in 2004 and 2006.

It’s unclear how many photographs may exist.

The government says it has 29 relevant images from at least seven different sites in Afghanistan and Iraq, and it’s believed to have perhaps hundreds or thousands more, Hellerstein said in a ruling in August.

He said some photos he had seen “are relatively innocuous while others need more serious consideration”.

He has ruled any images released would be redacted to protect the identities of people in them.

Some photographs, taken by service members in Iraq and Afghanistan, were part of criminal investigations of alleged abuse.

Some images show “soldiers pointing pistols or rifles at the heads of hooded and handcuffed detainees,” then-Solicitor General – now Supreme Court Justice – Elena Kagan wrote earlier in the case.

The government has long argued releasing the photographs could incite attacks against US forces and government personnel abroad.