Romania insisted Wednesday there was no evidence it had hosted secret CIA prisons as part of the United States' war on terror after September 11, 2001. The country "has no information whatsoever showing that there existed secret CIA detention centers on its territory," the Foreign Ministry told CNN. (See CNN's extensive coverage of America's war prisons.)

Two investigations also failed to find any evidence that the CIA used Romanian airports for "rendition," the process in which detainees in American custody are transported for questioning to other countries where prohibitions on torture are not as strict and American laws don't apply.

The Romanian denial comes in response to a plea from the human rights commissioner for the Council of Europe that countries that have hosted secret CIA prisons come clean. Thomas Hammarberg said Romania, Poland and Lithuania were among at least seven countries that hosted "black sites" for "enhanced interrogation" during the "war on terror."

"Darkness still enshrouds those who authorized and ran the black sites on European territories," he said. "The full truth must now be established and guarantees given that such forms of cooperation will never be repeated."

CIA officials have acknowledged the rendition program but have refused to discuss details and denied violating any laws. Efforts to challenge the agency and get details about it in U.S. courts have been turned aside. Hammarberg said the CIA held "high-value detainees," including alleged 9/11 mastermind Khalid Sheikh Mohammed, in Poland between 2002 and 2003.