The US Central Intelligence Agency (CIA) secretly operated illegal prisons for terrorism suspects in multiple locations in Poland and Romania from 2003 to 2005, according to a report released by the Council of Europe.

Senator Marty's report concludes that there is "now enough evidence to state that secret detention facilities run by the CIA did exist in Europe from 2003 to 2005, in particular in Poland and Romania". It also finds that prisoners in these facilities were subjected to "interrogation techniques tantamount to torture."

The report further suggests that President Aleksander Kwasniewski of Poland and former president Ion Iliescu of Romania authorized the secret detentions.

The Council of Europe report castigates the US and several European countries for these abuses. It also deplores what it terms "obstruction" by many of the governments implicated in the abuses, who "have done everything to disguise the true nature and extent of their activities and are persistent in their unco-operative attitude". In this respect, the report singles out the United States, Poland, Romania, Macedonia, Italy and Germany for criticism.

The report provides new information – including from cross-referenced testimonies of more than 30 current and former members of intelligence services in the US and Europe – about how the secret programme operated in Poland and Romania. It contains details from civil aviation records about CIA-operated airplanes used for detainee transfers, showing airplanes in the period 2003 through 2005 landing at remote airstrips in Poland and Romania. It also describes how flights to Poland – including one that may have carried terrorism suspect Khalid Sheikh Mohammed from Kabul to Szymany on March 7, 2003 – were deliberately disguised using fake flight plans.

CIA detainees were held in Poland until late 2005. They are believed to have been transferred out of the region after the Washington Post reported in November 2005 that the CIA was using detention sites in Eastern Europe and Human Rights Watch released information showing that Poland and Romania were likely among the sites used. ABC News, relying on sources within the CIA, reported in December 2005 that the detainees were flown to Morocco.

In September 2006, US President George W. Bush publicly acknowledged the existence of the secret CIA detention system, and announced that 14 prisoners in secret CIA custody had been transferred to the US military detention facility at Guantanamo Bay. In status hearings earlier this year, at least four of these 14 prisoners claimed that they had been tortured while in US custody.

Many detainees who are believed to have been held in CIA custody remain missing. Human Rights Watch has done extensive research on detainees believed to have been held by the CIA, and earlier this week issued an updated list of missing detainees jointly with five other human rights groups. The list named 39 persons whose fate and whereabouts are unknown.

However, the CIA dismissed the Council of Europe report - a CIA spokesman told the BBC that it was biased and distorted, and that the agency had operated lawfully.

Senator Marty's charge, that secret CIA prisons "did exist in Europe from 2003 to 2005, in particular in Poland and Romania", was also denied by both Polish and Romanian officials.

Polish former president Aleksander Kwasniewski, who served from 1995 to 2005, said on 8 June: "There were no secret prisons in Poland."

Romanian senator Norica Nicolai, who headed an investigation into the allegations, also denied his country's involvement.

"All statements made by Dick Marty are totally groundless," he said.