According to witnesses, police divide those at the gym into citizens and non-citizens. Russians are taken to enlistment offices, where their military records are checked.
Non-citizens are accused of immigration violations and given a choice: deportation, or enlistment in the army, according to Current Time, an independent Russian news platform.
It really is. The US took it a long time ago and now use it as a nearby place where it stores those its kidnapped without having to provide them with any legal counsel.