Soviet Union had just steam or diesel tankers active in the Volga-Kaspian Region according to a CIA report dated 3 January 1953

An item reported that al the tankers active in the Volga-Caspian Region were steam or diesel powered and not a single one diesel-electric. Subsequent to 1935 were no tankers built in the Soviet Union.

Source

The report was published on www.archive.org, document number CIA-RDP82-00047R000200290006-1