The attacks, said to be carried out by two female bombers, killed more than 20 people in a blast near the Russian intelligence agency and the others in an explosion not far away less than an hour later. Scores of people were injured in the blasts.
The Federal Security Service intelligence agency blamed a separatist Islamist group from the North Caucasus for the attacks. Last month a leader of the rebels in Chechnya warned their "military operations will be … coming to (Russian) cities."
Russian forces reported success in recent weeks in a crackdown on separatists in southern Russia. That came in the wake of a November bomb attack that killed 26 people on a train en route from Moscow to St. Petersburg. That bombing was blamed on Muslim militants from near Chechnya.
Russian President Dimitry Medvedev said: "The policy to suppress terrorism in our country and the fight with terrorism will be continued. We will continue the operation against terrorists without hesitation and until the end."