Kyrgyzstan's National Security Committee (GKNB) has named a 22-year-old Russian citizen as a suspect in Monday's deadly terror attack in St. Petersburg. The GKNB said that Akbarzhon Dzhalilov, born in the Kyrgyz city of Osh, could be linked to the blast which killed 14 people on the city's subway system.

Akbarzhon Dzhalilov

Fifty-one people were hospitalized following the explosion, which sparked a city-wide lockdown for much of Monday evening.

Investigators are currently treating the incident as a suspected suicide attack, with a homemade explosive device apparently packed inside a passenger's rucksack, the state-owned TASS news agency reported Tuesday. The bomb was also filled with small metal objects in order to cause greater damage, unnamed sources told the outlet.

The announcement follows a statement from the government of Kazakhstan, which said that the Russian media had wrongly identified a Kazakh student as part of the attack. Several other images of "potential suspects" released by the Russian press have also been dismissed as false.

Flowers being laid for #StPetersburg metro victims at Moscow's eternal flame, outside Kremlin. pic.twitter.com/fQFEnq1qr4 — Katie Davies (@katiedavies91) April 3, 2017

Three days of official mourning will take place across Russia, beginning on Tuesday.

The city’s subway system is now fully operational, despite a security scare at two stations early on Tuesday morning. The Grazhdancky Prospekt and Devyatkino stations were temporarily closed at 6:20 a.m. after commuters spotted “an unidentified object” on the track.