Yes it is, but it's not in the Kremlin, where the official seat is.

Both Stalin and Hitler were independent of their capital cities for conducting their rule. Dictators and emperors are not mere symbolic heads of state, and their network of people means much more than where they sit to conduct their business. This network is not necessarily connected to the capital.

I think we're maybe debating semantics, but I strongly disagree with the idea that the capital cities are more influential than the dictators and emperors. As in my example of Roman emperors who hardly even went to Rome.

Politics is much more about abstract human connections, than brick and stone buildings. We are a very mobile species after all.