According to media reports, Russian authorities said they were investigating a suspected suicide bombing on Monday after a blast on the Saint Petersburg subway system killed 11 people and wounded dozens.
The blast, which struck a crowded metro train near the city center at 2:20 local time, and came as Vladimir Putin was visiting the city.
“A blast occurred at Sennaya Ploshchad subway station,” a police source told the Russian news agency Tass, “Several people have been injured."
Witnesses on board the crowded train said it was shaken by a “thundering clap” that filled the carriages with smoke shortly after it left the station.
The driver of the train reportedly won praise for deciding to continue to the next station, Technologichesky Institute, rather than stopping in the tunnel, a move that investigators said probably saved lives and made it easier for rescuers to reach the injured.
Russia's president Vladimir Putin, who was meeting his Belarusian counterpart Alexander Lukashenko in a suburb of St Petersburg at the time, expressed his condolences after the “possible terror attack.”
“The city authorities, and if needed, the federal authorities, will take the necessary measures to help the families of those affected by the blast,” he said.
“The reasons behind it are not clear yet, and so it would be premature to speak about them,” he cautioned.
Meanwhile, the Interfax news agency, citing security sources, reported that the device was “homemade” with a blast equivalent to 200g of TNT.
Later on Monday, investigators said they believed the attack had been the work of a suicide bomber, and said the perpetrator was suspected to be a 23 year old from a Central Asian country.
A second bomb, disguised as a fire extinguisher, was late reported to have been found at the Ploshchad Vosstanaya subway station, which serves the mainline railway station that connects St Petersburg with Moscow.
The device, which apparently failed to explode, was reported to contain about 1 kilogram of TNT equivalent, prompting speculation that it was intended as the “main” attack.
According the Sputnik news agency, the Russian Investigative Committee has opened a terrorist act case following the deadly blast in the Saint Petersburg subway on Monday.
“Despite the fact that the criminal case has been launched under Article 205 of the Russian Criminal Code (terrorist act), the investigators will probe other potential causes of the incident," spokeswoman Svetlana Petrenko told reporters.
St.Petersburg authorities declared a three-day mourning in the city starting from Tuesday after the subway explosion.
