Ibárruri worked in the Executive Committee of the Communist International Secretariat at the Communist International Headquarters near the Kremlin. The work involved the continual evaluation, analysis and discussion of the progress of Communism outside the Soviet Union. This task was complemented by internal discussions in the PCE central committee which focused on Spain. No serious disagreement existed between the Communist Party of Spain and the Communist Party of the Soviet Union until 1968 over the Warsaw Pact invasion of Czechoslovakia. The PCE supported/excused Stalin's domestic and foreign policies, including the signing of the Molotov–Ribbentrop Pact on August 24, 1939.