By Adrian Krajewski and Noah Barkin
WARSAW (Reuters) - Poland promised on Thursday to release details of cockpit voice recorders from the plane crash that killed its president and dozens of other top officials in Russia, hoping to end speculation about who was to blame.
President Lech Kaczynski, Polish military leaders and senior opposition figures were traveling last Saturday to attend a ceremony marking the 70th anniversary of the massacre of over 20,000 Polish officers by Soviet secret police in Katyn forest when their plane went down.
Russian air traffic controllers in Smolensk say they urged the pilot to divert to another airport because of thick fog, but say he ignored the advice and made four attempts to land before hitting tree-tops and crashing.
Russia's Interfax news agency quoted senior aviation official Tatyana Anodina on Thursday as saying the plane made only one attempt to land, contradicting the earlier reports.
Some Polish media have speculated that Kaczynski, in his determination not to miss the Katyn event, may have ordered the pilot to try to land the plane against the Russians' advice.
"The conversations, their content, will be vital in terms of proving or disproving the various hypotheses. I will not oppose revealing the contents unless they are of an intimate nature," Andrzej Seremet, Poland's chief prosecutor, told Tok FM radio.
Interfax quoted what it said was a source close to the investigation commission saying the pilots did not seem to have been under pressure from Kaczynski.
"So far there is no evidence that any of the high-ranking passengers demanded that the pilots land at Smolensk. The voice recorder, whose decoding has been completed, did not register any pressure on the crew from their conversation," it said.
Russian investigators are decoding two cockpit voice recorders recovered from the Russian-made plane and a third Polish-made "black box" with flight data in it was to be returned to Poland on Thursday, Polish agency PAP reported.
Russian and Polish officials have indicated that they should finish reviewing the flight information in the next few days.
Speculation that Kaczynski may have ordered the pilot to land in Smolensk is based in large part on an incident in 2008, when the president flew to Georgia to show his solidarity with that country during its brief war with Russia.
Kaczynski grew irate when his pilot refused to land in the capital Tbilisi because of safety concerns, later accusing him publicly of cowardice for diverting to Azerbaijan and even pushing for him to be fired.
Belarussian leader Alexander Lukashenko, who has stormy relations with Warsaw after a crackdown on ethnic Poles, said Kaczynski, as president, had the "final say" and was thus responsible for the crash, according to Interfax.
Poland has been plunged into mourning and a presidential election brought forward to June from October.
About 70 of the 96 victims have been identified so far. Among many coffins returning to a solemn welcome in Warsaw on Thursday was that of Ryszard Kaczorowski, 90, head of Poland's London-based government-in-exile during the communist period.
Kaczorowski fought in the battle of Monte Cassino in Italy in World War Two and lived in exile in Britain after the war.
Thousands of people were still queuing at the presidential palace for up to 9 hours to pay their respects to Kaczynski and his wife Maria, two days after their coffins arrived there.
Biel-Flag, a Polish flag-making company, said it was struggling to cope with a surge in demand for red-and-white national flags following the tragedy.
"We are running out of material ... and had to hire new people to keep up with the orders, which are even more numerous than after (Polish) Pope John Paul II died," Chief Executive Jadwiga Gorkiewicz said, according to Polish news agency PAP.
OBAMA, MEDVEDEV, MERKEL
U.S. President Barack Obama, Russian President Dmitry Medvedev, German Chancellor Angela Merkel and French President Nicolas Sarkozy are among world statesmen and royalty expected for the funeral of Kaczynski and his wife on Sunday in Krakow.
Plans to bury the first couple at the Wawel Cathedral in the southern city, a place normally reserved for Poland's kings and national heroes, have sparked protests in Krakow and other cities from Poles who say Kaczynski does not deserve the honor.
Public support for Kaczynski, a polarizing nationalist and euroskeptic, had dwindled to just 20 percent before his death and polls showed he would have lost to Bronislaw Komorowski, the candidate of Prime Minister Donald Tusk's centrist Civic Platform (PO), in the presidential vote.
Komorowski, who is also speaker of parliament, became acting president after Kaczynski's death. It is unclear who will now be his main rivals in an election likely to take place on June 20.
Kaczynski had been the candidate of his twin brother Jaroslaw's right-wing Law and Justice (PiS). The candidate of the main leftist opposition party SLD also died in the crash.
Both parties are now under pressure to name new candidates.
(Additional reporting by Karolina Slowikowska, Patryk Wasilewski, Chris Borowski in Warsaw, Conor Humphries and Guy Faulconbridge in Moscow; writing by Noah Barkin)