Do you have a time period in mind when it was suppressed? To my knowledge, Soviet physicists contributed to general relativity and cosmology throughout the lifetime of the Soviet Union. One of the earliest solutions (and the most commonly used today) of the Einstein field equations was that produced by the Soviet scientist Alexander Friedmann in 1922-24. Later Soviet physicists working in the field include Lev Landau and Evgeny Lifshitz. They collaborated to produce a formalism that allowed the laws of conservation of energy and momentum to be reconciled with general relativity. Lifshitz also contributed, along with Belinsky and Khalatnikov to produce a model of the early universe, the BKL singularity. All of these scientists made significant contributions to general relativity, and worked in the Soviet Union for much of their careers.