A US-based civil rights group today asked German prosecutors to take legal action against the former US secretary of defence Donald Rumsfeld for war crimes.

The Centre for Constitutional Rights (CCR) lodged a complaint with the German federal prosecutor urging investigations of Mr Rumsfeld, who resigned last week, and other former US officials over alleged abuses in Iraq and at Guantánamo Bay.

Under a law enacted by Germany when the international criminal court was created in 2002, the federal prosecutor can investigate and prosecute war crimes regardless of where they are committed or of the nationality of the perpetrators.

The prosecutor dismissed a similar case brought by the CCR in 2004. But the CCR, backed by other civil rights groups, said new evidence, including signed memos, had now strengthened its case. It added that the former US brigadier general Janis Karpinski, a defendant in the earlier complaint as the commanding officer at Abu Ghraib prison in Iraq, was now providing testimony on behalf of the plaintiffs.

Ms Karpinski, who was relieved of her command and demoted to the rank of colonel last year, said her superiors had encouraged cruel treatment - though she denied having known about the abuses herself at the time.

In order to conceal what was going on at Abu Ghraib, those in charge of the prison had increased the scale of the abuses "incrementally over time", Col Karpinski said at a news conference alongside the lawyers backing the case.

She told Reuters Television: "When I look back at it now, when I see the footage, when I see the Iraqi people, I see a loss of hope in their faces. I see desperation in their faces, and I know that we in many ways contributed to this situation."

Mr Rumsfeld's resignation, on November 8, meant he could no longer claim the immunity sovereign officials enjoyed from international prosecution for war crimes, the CCR said.

The suit is brought on behalf of 12 alleged torture victims - 11 Iraqis held at Abu Ghraib and Mohamad al-Qahtani, a Saudi held at Guantánamo whom the US has identified as a would-be participant in the September 11 attacks.

"None of these plaintiffs - and the hundreds of other detainees subjected to similar abuses - has seen justice," the 220-page complaint said, "and none of those who authorised these techniques at the top of the chain of command have been held liable for it, or even seriously and independently investigated."

The CCR said Mr Qahtani had been subjected to 50 days of severe sleep deprivation, 20-hour interrogations, forced nudity, sexual and religious humiliation and physical force, including being made to adopt stress positions for long periods.

Besides Mr Rumsfeld, the action names the US attorney general, Alberto Gonzales, the former CIA director George Tenet, the former commander of all US forces in Iraq, Lieutenant General Ricardo Sanchez, and eight others. It alleges they ordered, aided or failed to prevent war crimes.

A case could not be brought with the international criminal court because the US was not a member, the CCR said; neither could it be pursued through the UN, because the US had power of veto.

The CCR also said the military commissions act of 2006, signed by George Bush, provided immunity for US officials and military personnel from prosecution for international crimes.

Wolfgang Kaleck, the German attorney leading the attempted litigation, said the suit's backers would appeal if prosecutors refuse to take up the case, and raised the prospect of further attempts in other European countries.

The Pentagon and the German federal prosecutor's office declined to comment, saying they had not yet received the suit.