"In attempting to combat crimes attributed to terrorists, countless further crimes have been committed in the course of the U.S.-led 'global war on terror,'" he said in a statement. "Many of those crimes have been carefully and deliberately covered up."

European governments were "deeply complicit" in U.S. counterterrorism strategies, including torture, Hammarberg said. In a 2007 probe, Swiss politician Dick Marty accused 14 European governments of permitting the CIA to run detention centers or carry out rendition flights between 2002 and 2005.

"They permitted, protected and participated in CIA operations which violated fundamental tenets of our systems of justice and human rights protection," Hammarberg said, adding that the governments involved have blocked proper investigations into rendition cases in line with Washington's wishes.

"The message is clear — good relations between the security agencies are deemed more important than preventing torture and other serious human rights violations," he said.