The Bush Administration gave the CIA wide authority to send terrorism suspects to foreign countries for interrogation just days after the September 11 attacks in 2001, the New York Times reported.
Citing current and former government officials, the newspaper reported President Bush signed a still-classified directive that gave the CIA a broad power to operate without case-by-case approval from the White House in the transfer of suspects - a process known as rendition.
The rendition program has been under scrutiny in recent weeks after several former detainees have complained of inhumane treatment and human rights groups have complained the operations violated American standards condemning torture.
While renditions were carried out before the Sept. 11 attacks, since then the CIA has flown 100 to 150 suspects to countries including Egypt, Syria, Saudi Arabia, Jordan and Pakistan, former government officials told the Times.
One current senior US official told the newspaper the program had been aimed only at those suspected of knowledge about terrorism operations and were transferred with promises they would not be tortured.
"We get assurances; we check on those assurances, and we double check on these assurances to make sure that people are being handled properly in respect to human rights," the official was quoted as saying.
He did not dispute there had been mistreatment on some occasions but said no one had died.
A half a dozen current and former officials told the New York Times the Bush administration may have turned a blind eye to torture.
"I really wonder what they are doing, and I am no longer sure what I believe," one former senior government official was quoted as saying.
The Bush administration has publicly said the United States did not hand over people to be tortured, the newspaper reported.