* ECHR says Poland did not provide details it requested
* Rights groups say CIA held Qaeda suspects on Polish soil
* Poland under pressure to investigate allegations
By Christian Lowe
WARSAW, Feb 5 (Reuters) - Poland has not answered questions put to it seven months ago by the European Court of Human Rights (ECHR) about whether the CIA ran a secret jail in Poland and how much Polish officials knew about it, the court said on Tuesday.
The absence of answers will add to pressure on Poland from human rights groups, who say it must prove it is committed to revealing the truth about what part it may have played in helping the CIA detain and interrogate al Qaeda suspects during Washington's "War on Terror" following the Sept. 11, 2001, attacks on the United States.
As part of a case brought to the ECHR by a Saudi man who alleges he was held in a CIA-run jail in a Polish forest, the court in July last year asked the Polish government to answer a list of questions about the alleged jail.
"To date, no such document has been submitted to the court," the court said in a statement to Reuters. "The government have only filed written submissions which reiterate information already made public."
The Polish government says it wants to co-operate fully with the Strasbourg court. But it argues that a criminal investigation underway inside Poland into the same allegations prevents it from answering the ECHR's questions.
That investigation is now in its fifth year with no sign of a conclusion. Rights activists accuse the Polish authorities of stalling the investigation because a trial could be politically embarrassing, though officials deny this.
Julia Hall of human rights group Amnesty International said if Poland was giving priority to its own investigation, not the European court's case, it had to show it was serious.
"We want to see the investigation in Poland concluded and for there to be the full truth about CIA operations in Poland."
Reports by bodies including the Council of Europe and the European Parliament state that between 2002 and 2005, CIA-chartered aircraft brought al Qaeda suspects to a remote Polish airfield. The detainees were driven to a Polish intelligence academy near the village of Stare Kiejkuty.
Once there, the reports say, CIA agents held the detainees with no court hearings or access to lawyers, and subjected them to interrogation techniques, including water-boarding, which rights activists say amounted to torture.
Polish officials deny publicly there was ever a CIA jail but they say they want a full and impartial investigation. Under Polish law and international treaties, assisting or failing to stop torture is a crime.
In a letter sent to the Strasbourg court on Sept. 5, the government said it was "not in a position to address in detail the questions submitted by the court or present the requested documents," because prosecutors in Poland were working on their own investigation.
"By addressing in detail the questions submitted by the court...the government could be seen as interfering with the competencies of the prosecution and judiciary authorities, which are independent of the government in Poland," the letter said.
Until now, the contents of the letter were unknown because the court had agreed to keep it confidential. The court has now made the letter public, though it said confidentiality could be offered if Poland submitted more information.
Polish officials reacted angrily to the decision to make the letter public, saying communications from the government to the court contained sensitive information.
"The decision of the court...is a threat to the security of Poles," Justice Minister Jaroslaw Gowin told state radio. "We must reconsider further cooperation with the court."
But Adam Bodnar, of the Warsaw-based Helsinki Foundation for Human Rights, said that argument did not stand up.
"What they submitted was already in the public domain, there was nothing new," Bodnar said.
The prosecutor's office in the southern city of Krakow, which is handling the Polish criminal investigation, said it had asked the Prosecutor-General for permission to extend the mission when it expires on Feb. 11.
(Additional reporting by Chris Borowski and Marcin Goettig in Warsaw and Wojciech Zurawski in Krakow, Poland; Editing by Angus MacSwan)