"I offer my sincere condolences to the families and friends of the victims ... While it is known that they are residents of the Ulyanovsk and Samara regions ... We will provide the victims and relatives of the victims with the necessary assistance," Azarov said in a video posted on Instagram.
The head of the region also said that all the victims were taken to the Syzran central city hospital, three of them are now being operated on.
According to the latest data, 12 people died in an accident, 12 more were injured.
Investigators are considering the maneuver of the bus as a preliminary cause of the accident.
A criminal case has been initiated into the incident.