Two human rights groups said Monday the government had provided official records for the first time confirming the landing in Poland of planes associated with the CIA's secret detainee program.
The data supports findings from a 2007 report by the Council of Europe on rendition flights, the Open Society Justice Initiative and the Helsinki Foundation for Human Rights said.
The groups said that flight logs provided by the Polish Air Navigation Services Agency under a Freedom of Information Act request revealed details about at least six landings in 2003 of a Gulfstream and a Boeing jet linked to the CIA at the former military airport of Szczytno-Szymany in northern Poland.
Adam Bodnar of the Helsinki foundation said the data confirmed what Polish leaders have denied.
"This is an official confirmation coming from a state-run agency," he told reporters. "The authorities can no longer ignore facts."
A 2005 Human Rights Watch report claimed the U.S. spy agency transported suspected terrorists captured in Afghanistan to Poland, where they were held in secret prisons.
Poland has repeatedly denied the claims, but has opened a prosecutors' investigation, which is still under way. Its findings so far have remained classified.
Prosecutor Robert Majewski, who is in charge of the investigation, said Monday he was not familiar with the flight logs.
Airport officials and border guards at Szczytno-Szymany airport, have previously confirmed that a Boeing passenger jet with U.S. citizens aboard landed there Sept. 22, 2003 the date Human Rights Watch said a Boeing 737 that was part of the prisoner transfer scheme was at the airport.