(ANSA) - SOFIA, SEPTEMBER 9 - Tensions between Sofia and Moscow over September 9, 1944, which marked the arrival of the Soviet troops in Bulgaria. The Russian embassy in Sofia responded to the criticism expressed by the Bulgarian Foreign Ministry of an exhibition organized in the Bulgarian capital city to commemorate the arrival of the Red Army in the country on September 9, 1944. According to Sofia-based media, in a statement issued last Tuesday, the ministry expressed strong criticism of the use of the word "liberation" to describe the entry of Soviet troops at the end of WW2, underlining that "the Soviet bayonets marked the beginning of decades of oppression for Bulgaria". Furthermore, Bulgarian diplomacy accused the Russian embassy of interference into the country's internal affairs, pointing out that "such issues would have been better left to the historians' assessment". The Russian diplomatic mission said that the exhibition, which opens today in the Russian Cultural Center in Sofia, is focused on the 75th anniversary of the liberation of Eastern Europe from the Nazis and "has nothing to what to do with today's internal Bulgarian political debate or with individual political forces". "We are therefore surprised that a formal statement could be released before the inauguration of the exhibition itself," the Russian Embassy said. (ANSA).