The state archive shows a March 1940 letter to Stalin from his secret police chief Beria ordering the killings
Russia's state archive has published formerly top secret Soviet-era documents on the April 1940 Katyn massacre on its website.
They include a key letter to then Soviet leader Joseph Stalin from secret police (NKVD) chief Lavrenty Beria, dated 5 March 1940 and marked "Top Secret".
Some 22,000 members of the Polish elite were killed by Soviet forces, and for decades the USSR claimed that it was the work of Nazi Germany. Russia gave the documents to Poland in 1992.
Here are excerpts from the Beria letter:
"To Comrade Stalin:
In prisoner-of-war camps run by the USSR NKVD and in prisons in western Ukraine and Belorussia there is currently a large number of former Polish army officers, former officials of the Polish police and intelligence services, members of Polish nationalist counter-revolutionary parties, members of unmasked rebel counter-revolutionary organisations, defectors and others. They are all sworn enemies of Soviet power, filled with hatred towards the Soviet system.
The POW officers and police in the camps are trying to continue counter-revolutionary work and are engaged in anti-Soviet agitation. Each of them is just waiting for liberation so as to actively join the struggle against Soviet power
Beria, a Georgian like Stalin, was notorious for enforcing a reign of terror
In total in the prisoner-of-war camps (not counting soldiers and non-commissioned officers) there are 14,736 former officers, government officials, landowners, policemen, military police, jailers, settlers and spies. More than 97% are of Polish nationality
In total the prisons of western Ukraine and Belorussia contain 18,632 detainees (of whom 10,685 are Poles)...
Based on the fact that all of them are steadfast incorrigible enemies of Soviet power, the USSR NKVD deems it essential:
I. To propose that the USSR NKVD: [underlined - ed]
Give special consideration to
1) the cases of 14,700 people remaining in the prisoner-of-war camps - former Polish army officers, government officials, landowners, policemen, intelligence agents, military policemen, settlers and jailers,
2) and also the cases of those arrested and remaining in prisons in the western districts of Ukraine and Belorussia, totalling 11,000 - members of various counter-revolutionary spy and sabotage organisations, former landowners, factory owners, former Polish army officers, government officials and defectors -
Imposing on them the sentence of capital punishment - execution by shooting.
II. The cases are to be handled without the convicts being summoned and without revealing the charges; with no statements concerning the conclusion of the investigation and the bills of indictment given to them
[The letter is signed "L. Beria" in blue pencil, under the title USSR People's Commissar for Internal Affairs.
The first page of the letter bears the word Za - "in favour" - scrawled in blue pencil with the signatures of then Soviet leader Joseph Stalin and of Politburo members K. Voroshilov and A. Mikoyan, along with V. Molotov in ordinary pencil. In the margin are the names Kalinin and Kaganovich - also aides to Stalin - added in blue ink, and also with the word za.]