Russian ITAR Tass news agency announced the death of 20 people in the first explosion in Lubyanka station of the Moscow subway network. 11 others are reported to be wounded.
Russian Emergency Ministry said the station was located under the headquarters of Russian Federal Security Service.
45 minutes after the first explosion, another big blast hit Park Kultury station. Initial announcement says at least 12 people were killed in the second explosion.
Officials said the explosions were the job of two women suicide bombers.
Noone claimed responsibility for the attacks yet.
News agencies report the death toll might increase in the coming hours.