FACTBOX: Secret prison allegations on Poland, Romania

(Reuters) - A European investigator said on Friday he had proof of long-standing allegations that Poland and Romania housed secret CIA prisons on behalf of the United States to help in its war on terrorism. Both countries deny it.

Here are key points from the report by Council of Europe investigator Dick Marty.

WHY POLAND AND ROMANIA?

Washington chose the two countries because they were "economically vulnerable, emerging from difficult transitional periods in their history, and dependent on American support for their strategic development". Both were eager to secure their status as key NATO members and friends of the United States.

SECRET DEALS

"The CIA brokered 'operating agreements' with the governments of Poland and Romania to hold its high-value detainees (HVDs) in secret detention facilities on their respective territories. Poland and Romania agreed to provide the premises in which these facilities were established, the highest degrees of physical security and secrecy, and steadfast guarantees of non-interference," the report said.

The CIA chose Polish and Romanian "point men" who vouched for the reliability and secrecy of their national services. The CIA limited to an absolute minimum the number of Polish and Romanian counterparts who knew about even "tiny little pieces" of the operations.

In both countries, the agency worked with the military intelligence agencies, which offered greater levels of secrecy than their civilian counterparts.

WHO KNEW?

For the first time, Marty named top Polish and Romanian officials who, he said, knew of and could be held accountable for the operation of secret CIA prisons in their countries.

In Poland: then-president Aleksander Kwasniewski, head of National Security Bureau Marek Siwiec, defense minister Jerzy Szmajdzinski and military intelligence head Marek Dukaczewski.

In Romania: former president Ion Iliescu, current President Traian Basescu, former presidential adviser on national security Ioan Talpes, former defense Minster Ioan Mircea Pascu and head of military intelligence directorate Sergiu Tudor Medar.

WHEN, WHERE AND HOW

From the first half of 2003, Poland housed some of the CIA's most sensitive prisoners, including senior al Qaeda figures Abu Zubaydah and Khalid Sheikh Mohammed, who says he masterminded the September 11 attacks on the United States. Both were subjected to 'enhanced interrogation techniques'.

In Poland, CIA flights used the northern airport of Szymany. Dummy flight plans were filed to disguise the destination. Secret flights were met at the end of the runway, out of visible range of the terminal, by a team of American officials in vans; the vans then drove through thick pine forest and along the side of a lake to reach the Stare Kiejkuty intelligence training base where the prisoners were held.

The Romanian 'black site' operated between 2003 and the second half of 2005, housing prisoners whose intelligence value had been assessed as lower. CIA flights used the air force base at Mihail Kogalniceanu airfield, Marty said.