The explosion occurred in a subway train car, on the stretch between the two central stations at about 3 p.m. local time (12:00 GMT).
"Following the order of St. Petersburg governor, one million rubles will be allocated from the reserve fund to the families of victims, those with serious injuries will be paid 500,000 rubles and those with light injuries — 250,000 rubles," Kibitov said.
According to Russia's National Anti-Terrorism Committee (NAK), at least 11 people were killed and 45 others were wounded in the blast. Russian Health Minister Veronika Skvortsova earlier said at least 10 people were killed and 37 others injured.
Russia's Investigative Committee has opened a criminal investigation into a suspected terrorist attack and would also look into all potential lines of inquiry.