Law enforcement officers have uncovered around 300 illegal migrants in an apartment building in the Tver Region, according the local Interior Ministry.
The migrants, who were living in an unfinished, 97-apartment building, come from Tajikistan, Uzbekistan and Kyrgyzstan, police said.
The illegals were taken by police to a local precinct, where they were charged with violating Russian migration law, an Interior Ministry source said.
Russia has long battled with illegal migration, especially from countries in Central Asia and the Caucasus.