As early as 1947 Sergei Lebedev had set up a secret laboratory and set about building a small computer called MESM (МЭСМ, Малая Электронно-Счетная Машина) Malaya Elektronno-Schetnaya Mashina or Small Electronic Calculating Machine. It was the earliest, fully operational electronic computer in the Soviet Union - and indeed continental Europe but getting it accepted was far from an easy process.
МЭСМ - Malaia Elektronnaia Schetnaia Mashina
The story is told in detail in I Programmer's history article, Sergei Lebedev and Early Russian computers and in this video Boris Malinovsky, who worked on MESM and is now a leading expert on Soviet-era computing, talks about Lebedev and MESM:
If you don't speak Russian click the Caption button for subtitles.