MOSCOW Russia handed over to Poland more documents on the 1940 massacre of Polish officers on Friday, three days before President Dmitry Medvedev visits Warsaw in a further sign of improving relations.
Russia passed on 61 volumes relating to the event, in which 22,000 Polish prisoners of war were killed by Soviet troops in the Katyn forest.
"We have not analyzed the volumes yet in detail, but this means that most of the Katyn files are in our hands now," Polish Foreign Minister Radoslaw Sikorski told Reuters.
Medvedev handed over a similar batch of documents on the Katyn massacre in May, shortly after Polish President Lech Kaczynski and dozens of other senior officials were killed in a plane crash in Russia while traveling to the site to mark the 70th anniversary of the tragedy.
"Difficult pages of our common past should not impact negatively our current and future relations," a Kremlin official, who spoke on condition of anonymity, also said.
Poland's Prime Minister Donald Tusk said on Friday he hoped to get the wreck of the plane back to Poland before the first anniversary of the crash next April.
Last week, in a vote widely seen as an attempt by Moscow to improve ties, the lower house of the Russian parliament approved a resolution naming Soviet leader Josef Stalin for the first time in a public document as guilty of the killings.
Warsaw wants Russia to rehabilitate the Katyn victims' families and Sikorski said he hoped Moscow's recent gestures would pave the way for this eventually.
"This is conducive to establishing legal peace between the Russian Federation and the Katyn families," Sikorski said.
The original 1940 execution order signed by Stalin was declassified by Russian President Boris Yeltsin in 1990, a year after the fall of communism in Poland and after decades during which Moscow blamed the Nazis for the massacre.
"Katyn is one of the major symbolic issues that hurt Russian-Polish relations for many years," said Nikolay Petrov, an analyst at Carnegie Endowment in Moscow.
"The passing over of these documents is about their historic memory as a monument to the victims and a demonstration of goodwill and reconciliation ahead of Medvedev's trip."
Medvedev is expected to discuss energy, trade and security issues, including missile defense, in his talks with Polish President Bronislaw Komorowski on Monday.
Tusk's center-right government is trying to build closer economic ties with its energy-rich neighbor, despite disagreements over NATO enlargement, missile defense and aspects of history.
Medvedev is also due to lay flowers at a memorial to Soviet soldiers during his two-day visit on Monday and Tuesday.
Bilateral trade was worth 15 billion dollars in the first nine months of 2010, or 1.5 times more than in the same period in 2009. The bulk of the trade is composed of Polish imports of Russian gas.