"Peace, to which all people are obliged in the name of Christ, should be based not on political or personal ambitions, but on love and co-operation," Patriarch Alexei II said.
More than 100 people were killed after Soviet tanks rolled into Prague 30 years ago today to halt nine months of reforms - including free speech - never before seen in the Soviet bloc.
The Patriarch said the Soviet invasion brought "much sorrow" to the Czech people. "Similar feelings are caused by memories of bloodshed in Berlin in 1953, in Budapest in 1956 and in Afghanistan in the 1980s," he added.
In a telegram to the Congress of Russia Intellectuals, Mr Yeltsin said: "Even shy attempts of reform called down terror from those who wanted to preserve the totalitarian system." AP