A device detonated on a train between the Sennaya Square and Technology Institute Metro stations in St. Petersburg, Russia, around 2:40 p.m. on April 3, killing at least 10 people and injuring at least 50 others, according to Kommersant and other leading Russian outlets. Reports that a second device was defused at the Ploshchad Vosstaniya station are unconfirmed. Russian authorities shut down the entire St. Petersburg Metro system and have called the bombing a terrorist attack.
Given the amount of white smoke present in the station immediately after the bombing and the reports of nails added to the device, it was either an acetone peroxide — also known as TATP — bomb or a pressure cooker-type device that used a low explosive such as black powder and contained additional shrapnel. It was not an accidental explosion.
Constructing this simple device is well within the capabilities of militant groups operating in Russia, or even of grassroots jihadist sympathizers, mainly from the country's restive North Caucasus region. Russian authorities have previously arrested Islamic State sympathizers involved in synthesizing TATP and have sought to prevent the group's militants returning from the battlefields in Syria from launching attacks more generally.
Russia's homegrown jihadist groups, in particular the Caucasus Emirates, have perpetrated similar attacks in the past. But the St. Petersburg attack is the largest outside of the Russian Caucasus since the December 2013 Volgograd train station bombings. There have also been several terrorist attacks directed against targets in Moscow, including several suicide bombings on the Moscow Metro and a suicide attack against Domodedovo International Airport in 2011.
The timing of the attack is significant, occurring just after Russian President Vladimir Putin held his yearly All-Russian People's Forum — a political event that includes a group of pro-Putin organizations and is meant to sow public trust in the president. It is also notable that Putin is in the city to meet with Belarusian President Aleksandr Lukashenko. Though the attack was not targeting the Russian president or other officials, it is a clear message to the Putin government, which has taken a hard line against the nation's jihadist sympathizers. Given the recent demonstrations against the government across Russia, the possibility that angry protesters might have perpetrated the bombing cannot be ruled out either, though initial suspects lean toward jihadists.
Whoever is responsible, terrorism ultimately plays into the Kremlin's agenda. The St. Petersburg bombing could embolden the Russian government to increase security measures across the country and to crack down on any dissidence.