Metro commuters have described scenes of horror Monday following the subway blast in St. Petersburg, Russia.
Stanislav Listyev told CNN: "I was going down the escalator at Sennaya Square at about 2:30 pm -- and at that moment I felt an explosion wave underneath, everything filled with smoke, people started panicking.
"So the trains stopped and almost immediately the evacuation started. I think that explosion happened in the tunnel between the stations. The smoke was coming out of there. There was nothing on the station itself, everything was fine."
An unnamed eyewitness who spoke to the state news agency, Tass, said: "In the metro car, everyone expected death, if I can say that."
"After the explosion, everyone expected consequences, then we were taken out, and people began to help each other, brought others out, most were covered in blood."
Another witness told Tass that they waited for evacuation for several minutes after the explosion, which took place between the Sennaya Ploshchad and Tekhnologichesky Institute stations in central St. Petersburg.
"I saw dead people, 3-4 people minimum, the emergency services arrived after 5-7 minutes," he said.
A woman interviewed by Life News in Russia said: "The people were bloody, they had their hair burned. Smoke came out of the cars. We were told to move to the exit, because the traffic was stopped. People just ran.
"My friend was in a metro car near to the one which exploded. She said it shook. When she came out, she saw that people were all disfigured."
St. Petersburg resident Leonid Chaika, who said he was at the station where the blast happened, told Reuters: "I saw a lot of smoke, a crowd making its way to the escalators, people with blood and other people's insides on their clothes, bloody faces. Many were crying."
Geoff Edwards, 68, from Liverpool, England, works in St. Petersburg. He told the BBC he is a quarter of a mile away from the scene.
"There are helicopters flying around right now, I can hear them out of the window," he said. "A colleague told me that one landed near the station -- to collect dead bodies. "
Meanwhile Instagram user @a_shevala posted a video of emergency responders at Sennaya Square in the aftermath.
And Instagram user @kuchynskaya shared a video of ambulances rushing to the scene and then racing away to the hospital.
At least 11 people are reported dead, and at least 20 are injured.