Pakistani spy agency ISI's detention facilities in Karachi and elsewhere were used as an initial detention and interrogation point by the CIA during America's war on al-Qaeda which was supported by over 50 countries following 9/11 attacks, a new report has claimed.

The report authored by Amrit Singh, daughter of Prime Minister Manmohan Singh, says over 50 countries assisted the US in its war against al-Qaeda including by hosting CIA prisons on their territories and detaining, interrogating and "torturing" terror suspects.

It said detention facilities in Pakistan in which detainees were held at the behest of the CIA include the ISI detention facility in Karachi, which was allegedly used as an initial detention and interrogation point before detainees were transferred to other prisons.

Although controlled by the ISI, detainees at the facility claim to have been interviewed by both US and British intelligence officials.

The report 'Globalising Torture - CIA Secret Detention and Extraordinary Rendition' released today by rights advocacy group Open Society Justice Initiative details the involvement of 54 nations in the American campaign against al-Qaeda and identifies 136 people who had been held or transferred by the CIA, describing when and where they were held.

Singh said she had found evidence that prisoners were held in countries like Thailand, Romania, Poland and Lithuania while Denmark facilitated CIA air operations.

The report provides the number of known victims of secret detention and extraordinary rendition operations, in which suspects were transferred from one country to another without any legal process.

Singh, who joined the Open Society Initiative in 2009 as senior legal officer for national security and counter- terrorism, said: "moral cost of these programmes was borne not just by the US but by the 54 other countries it recruited to help."