Russia made public for the first time today documents relating to the 1940 execution of 22,000 Polish officers by the Soviet NKVD secret police, including an order signed by Josef Stalin.
President Dmitry Medvedev released the material in the latest of a flurry of gestures of solidarity with Warsaw since Polish president Lech Kaczynski, his wife and 94 officials were killed on April 10th in a plane crash en route to a ceremony commemorating the Katyn massacre in western Russia.
Russia's Federal Archive Service, or Rosarkhiv, published on its website www.rusarchives.ru scanned photos of several documents, including a March 5th, 1940, note from NKVD head Lavrenty Beria - signed by Stalin and three other members of the Soviet Politburo – ordering the execution of Polish "nationalists and counter-revolutionaries".
Mr Medvedev described the publication as a "duty".
"Let people see it, let them know who made the decision to kill the Polish officers," Mr Medvedev said during a trip to Copenhagen.
"It's all there in the documents. All signatures are there, all the faces are known."
Mr Medvedev added that he had ordered a number of Katyn documents still in Russia's hands to be passed to Warsaw.
Katyn is an enduring symbol for Poles of their suffering at Soviet hands in the 20th century. For decades, Moscow blamed the Nazis for the massacre and only acknowledged its responsibility in 1990, a year after the fall of communism in Poland.
The Kremlin has resisted Polish calls to brand the Katyn massacre "genocide."
The published documents and their contents have been known to historians, politicians and families of those killed since the early 1990s but this is the first time most Russians have been able to see the scanned originals.
The publication is also a further sign that long-running tensions between Russia and Poland are easing. Mr Medvedev braved the closure of European airspace caused by a volcanic ash cloud on April 18th to attend Mr Kaczynski's funeral in Krakow and to tell Poles he hoped the tragedy could bring the two nations closer.
There are 183 volumes of documents relating to the 1990-2004 investigation, and 116 of them are still closed.
Reuters