Cleared for travel to Eastern Bloc countries, in 1966 he was part of a delegation visiting East Germany, and in 1969 and 1974 visited Bulgaria. In August 1968 the Soviet Union led an invasion of Czechoslovakia to put an end to the Prague Spring, a period of political liberalization in the Marxist–Leninist country. Although Gorbachev later stated that he had had private concerns about the invasion, he publicly supported it. In September 1969 he was part of a Soviet delegation sent to Czechoslovakia, where he found the Czechoslovak people largely unwelcoming to them. That year, the Soviet authorities ordered him to punish Fagien B. Sadykov, a Stavropol-based agronomist whose ideas were regarded as critical of Soviet agricultural policy; Gorbachev ensured that Sadykov was fired from teaching but ignored calls for him to face tougher punishment. Gorbachev later related that he was "deeply affected" by the incident; "my conscience tormented me" for overseeing Sadykov's persecution.