Since you may not reliably determine the citizenship via traffic routes, probably, it's better to ask user during signup about his country (simple pre-filled "W

Since you may not reliably determine the citizenship via traffic routes, probably, it's better to ask user during signup about his country (simple pre-filled "Where are you from?" question, true answer on which is required by ToS) and then route his data through a native (Russian, Chinese etc) server, which can store it and "request" further processing overseas (this fulfills all the requirements of the law, including both storage and primary processing).