At Least 9 Killed In St. Petersburg Metro Explosion

No fewer than 9 people were killed and 20 were injured after an explosion rocked a train in St. Petersburg, Russia on Monday.

The source of the explosion was a bomb filled with shrapnel, which detonated at 2:20 p.m. local time on a metro train traveling from the Technology Institute station to the Sennaya Square station.

Another bomb was deactivated at a separate St. Petersburg metro station shortly after the first blast, according to the Associated Press.

Russian President Vladimir Putin, who was visiting the city on Monday, said that investigations were underway to determine the cause of the attack. At the time of reporting, no group or individual has claimed responsibility for the explosion.

“Law enforcement agencies and intelligence services are doing their best to establish a cause and give a full picture of what happened,” the Russian president said.

Russia has been the target of terrorist attacks carried out by Chechen separatists. In March 2010, double suicide bombings in Moscow killed 40 people in an attacked claimed by Chechen separatist Doku Umarov.