Poland threatened to halt the transfer of al-Qaida suspects to a secret CIA jail on its soil 11 years ago, but became more "flexible" after the Central Intelligence Agency handed over a large sum of money, according to a U.S. Senate report.

U.S. President Barack Obama discussed the report's forthcoming publication during a telephone call on Monday with Polish Prime Minister Ewa Kopacz, administration officials and the Polish government said.

The heavily redacted report does not mention Poland. But it is clear it refers to the country because details including the names of three detainees and the dates they were transferred match other documents, including a European Court of Human Rights ruling relating to a CIA-run "black site" in Poland.