St. Petersburg Governor Georgy Poltavchenko has ordered that the relevant city agencies work in line with a special plan for emergency situations in the wake of the reported incidents in the city's metro system.

"The St. Petersburg governor has been informed about what has happened. All relevant agencies have been ordered to work in the emergency mode," Poltavchenko's press secretary Andrei Kibitov told Interfax on Monday.

"Under the governor's instructions, all relevant city agencies are working in line with the plan of operations developed for emergency situations," Kibitov then later on Twitter.