WASHINGTON: Fifty-four foreign governments assisted the CIA in a global campaign that included harsh interrogations of suspects, a rights advocacy group said Tuesday, as it pressed for greater accountability.

The report by Open Society Foundations marks the most comprehensive list of countries that helped the United States in what critics saw as excesses by then president George W. Bush's administration after the September 11, 2001 attacks.

Bush authorized "extraordinary rendition" -- the transferring of individuals without legal process -- to allow US and foreign intelligence agencies to interrogate alleged extremists outside the protections ensured on US soil.

The Open Society Foundations found evidence that 54 foreign governments supported the system by actions such as hosting CIA prisons, interrogating suspects, allowing airspace for secret flights or providing intelligence.

Many of the cases involve countries that have long fought Islamic militants on their home territory such as Afghanistan, Egypt, Pakistan and Saudi Arabia.

The report also listed close US allies such as Australia, Britain, Canada, Denmark, Finland, Germany, Ireland, Italy, Poland, Spain, Sweden, Turkey and Thailand.

South Africa was listed in part due to allegations the Pretoria government gave US intelligence the green light in 2003 to abduct Saud Memon, a Pakistani suspected in the slaying of Wall Street Journal reporter Daniel Pearl.

Memon died shortly after his release in Pakistan in 2007.

The study also listed Iran, saying that despite poor relations with the United States, Tehran indirectly handed over at least 10 suspects -- mostly Arabs -- to US custody via the Kabul government.

The report called for accountability both in the United States and overseas, saying there was "no doubt" that Bush administration officials authorized what it called human rights violations.

"By engaging in torture and other abuses associated with secret detention and extraordinary rendition, the US government violated domestic and international law, thereby diminishing its moral standing and eroding support for its counterterrorism efforts worldwide," the report said.

But it said responsibility "does not lie solely with the United States, but also with the numerous foreign governments without whose participation secret detention and extraordinary rendition operations could not have been carried out."