 By late 1942 and early 1943, as the Soviet Union's position was boosted by its military victories, Czechoslovak-Soviet cooperation became much stronger; on 12 November 1942, the Czechoslovak side suspended talks with the Poles until permission from the Soviet Union had been obtained, and on 10 February 1943, the Czechoslovak diplomat Hubert Ripka informed the Polish government that no agreement that could be seen as antagonistic towards the Soviet Union would be supported by the Czechoslovak government.That was a major blow to the Polish-Czechoslovakian negotiations.Soon afterward, Poland and the Soviet Union broke diplomatic relations over the Katyń massacre.