There is not a single Pole who would not be deeply shocked by the news widely publicized by the German propaganda about the discovery of a mass grave near Smolensk that contains the mangled bodies of missing Polish officers who vanished in the USSR and about the way in which they perished. On April 15 the Polish government ordered its representative in Switzerland to turn with a request to the International Red Cross in Geneva to send a delegation to the site to examine the existing situation. [...]
Simultaneously, the Polish government, acting on behalf of the Polish Nation, refuses the Germans the right to use the crime which they attribute to others as an argument serving the purposes of their own defence. The hypocritical outcry of the German propaganda will not help conceal from the world the repeated and continuing cruel crimes against the Polish Nation. [...] The Polish government condemns all crimes committed on Polish citizens and refuses to allow anyone who is guilty of crimes against the Polish Nation and State to use the victims of such crimes for the purpose of political games.
London, April 17, 1943
Stosunki Rzeczypospolitej Polskiej z państwem radzieckim 1918-1943. Wybór dokumentów (Poland's Relations with the Soviet State 1918-1943. Selected Documents), ed. Jerzy Kumaniecki, Warsaw 1991