PHOTO: A Metro station in the Russian city of St. Petersburg. (photo via Flickr/sbamueller)
An explosion has rocked a metro station in St. Petersburg, Russia. Several people have been reported dead and as many as 50 have been injured, according to Russian state news agencies.
The blast occurred near the Tekhnologichesky Institute station on a train arriving from Sennaya Square station. Another device was discovered near the Vosstaniya metro station, but it did not detonate.
The site of the blast is some distance from main St. Petersburg tourism attractions. However, the area is still in the historic center of the city.
Because it is early on in the stages of the investigation, rescue workers expect the number of deaths and injuries to increase.
Russian president Vladimir Putin has said that terrorism is not being ruled out and that all causes are being investigated. Putin, was in St. Petersburg earlier on Monday, says his Kremlin spokesman and, according to The New York Times, he was in the city when the blast occurred.
A witness told CNN that he saw smoke coming from a tunnel.
"I was going down the escalator at Sennaya square at about half past 2, and at that moment I felt an explosion wave underneath. Everything was filled with smoke, people started panicking. So the trains stopped and almost immediately the evacuation started," Stanislav Listyev told CNN.
The metro in St. Petersburg is among the world’s busiest, with 2 million riders using it for transportation each day.
(Stay tuned for updates as we follow this story.)
NOTE: Due to conflicting reports, previous updates have included a number of casualties that may not be accurate because of incomplete information. The original story has been updated to reflect this.