HRW called for investigating Rumsfeld “for potential liability in war crimes and torture by US troops in Afghanistan, Iraq and Guantanamo under the doctrine of ‘command responsibility’ - the legal principle that holds a superior responsible for his subordinates' actions when he knows, or should know, that crimes are being committed but fails to stop them.”

It underlined that the defense secretary approved interrogation techniques - such as the use of guard dogs to frighten prisoners and painful “stress” positions - that violated the Geneva Conventions.

Citing an investigative report by famed journalist Seymour Hersh, the report said that Rumsfeld “authorized the establishment of a highly secret program that was given blanket advance approval to kill or capture and, if possible, interrogate high value targets in the war on terror.”

HRW again criticized Rumsfeld for thumbing his nose at international law and the Geneva Conventions.

“Rumsfeld’s belittling of the Geneva Conventions created a climate in which respect for legal norms by US troops may have been loosened.”

The report quoted Rumsfeld as ridiculing the Conventions during his visit to Abu Ghraib prison on May 14, where he told American soldiers: “Geneva doesn’t say what you do when you get up in the morning”.

In the first legal action against a senior US official on the abuse of detainees, Rumsfeld is already being sued by two civil liberties groups for his “direct responsibility” in the illegal torture and prisoners' abuses.

The lawsuit was filed by the two groups on behalf of eight detainees, four Iraqis and four Afghans, who were subjected to torture, beatings, cutting with knives, assault, sexual humiliation, mock executions and other illegal treatment.

The report said that when a government as dominant and influential as the US openly defies laws against torture, it virtually invites others to do the same.

“The coercive methods approved by senior US officials and widely employed over the last three years include tactics that the US has repeatedly condemned as barbarity and torture when practiced by others,” it asserted.

The HRW special counsel said that Washington, in withholding evidence and papering over war criminals, has become a mirror image of “dictatorships and banana republics.”

“When their abuses are discovered—cover up the scandal and shift blame downwards,” he said.

“If there is no real accountability for these crimes, for years to come the perpetrators of atrocities around the world will point to the US’s treatment of prisoners to deflect criticism of their own conduct,” the report warned.

The US-based rights group further cited overwhelming evidence that US mistreatment and torture of “Muslim prisoners” took place not merely at Abu Ghraib and Guantanamo but at “secret locations” worldwide.

“In many cases the abuse resulted in death or severe trauma, and that a good number of the victims were civilians with no connection to Al-Qaeda or terrorism,” it maintained.

“There is also evidence of abuse at US-controlled secret locations abroad and of US authorities sending suspects to third-country dungeons around the world where torture was likely to occur.”

The American Human Rights First charged in 2004 that Washington has more than 24 world detention camps, at least half of them operate in total secrecy, where the abuse of detainees is “inevitable”.

Earlier, The Observer accused the US and its allies of running a wanton global network of detention camps allowing Washington to fly so-called terror suspects to other countries where they are tortured for information.