The CIA torture report details the techniques used on detainees held at secret prisons worldwide. Getty Images

Former Polish president Aleksander Kwasniewski has conceded for the first time that the country has allowed the CIA to run a secret prison on its territory, but stopped short from saying that Polish officials authorised torture of its inmates.

The acknowledgement came after the US Senate published a damning report on the CIA's controversial interrogation programme which found that agency officials routinely misled the White House and Congress about the information it obtained under torture. CIA's practices were far less effective and more brutal than the agency acknowledged. The agency also failed to provide basic oversight of the secret prisons it set up around the world.

The heavily redacted report does not mention Poland but it refers to the eastern European country when it mentions the names of three detainees and the dates they were transferred. That matches other documents including a European Court of Human Rights ruling linked to a CIA-run "black site" in Poland.

The report also hints that Poland threatened to stop the transfer of al-Qaeda suspects to the jail but became more "flexible" after the agency gave it a large sum of money.

Kwasniewski, who was in power from 1995 to 2005, said the CIA prison was indeed halted under pressure from Poland's leaders. "Poland took steps to end the activity at this site and the activity was stopped at some point," Kwasniewski said on Radio TOK FM.

He said he pressured former US president George W. Bush to end intelligence activity in the country.

The Senate report recounts how the CIA programme strained relations with Poland, one of Washington's strongest European allies.

"The agreement to host a CIA detention facility in Country [] created multiple, ongoing difficulties between Country [] and the CIA," the report said. All mentions of the name of the country were blacked out.

The agency refused to accept a Polish proposal to define CIA's roles and responsibility at the facility. Poland then refused to accept the planned transfer of new detainees, only to reverse it under the payment of a massive sum.

"The decision was reversed only after the U.S. ambassador intervened with the political leadership of Country [] on the CIA's behalf. The following month, the CIA provided $[] million" to the country, the report said.

Following the exchange of money Poland "was now flexible with regard to the number of CIA detainees at the facility and when the facility would eventually be closed," according to the report.

The Washington Post said former CIA officers paid $15m to Polish intelligence in 2003 for the site.

A 2007 Council of Europe report stated that Poland's CIA "black site" was located at the Stare Kiejkury military training facility, where high-value detainees were subjected to harsh interrogations.