MOSCOW: The explosion in the St Petersburg metro went off between two stations with a "thundering clap", a survivor of the metro blast said on Monday (April 3).
The student, who gave her name only as Polina, was in the neighbouring car when the blast - which Interfax news agency said was caused by a bomb filled with shrapnel - went off.
At least 11 people were killed and more than 40 injured when the blast tore through a train carriage in the underground system on Monday, between the Technology Institute station and the Sennaya (Ploshchad) station.
"We were riding in the neighbouring car, and at that time it was very crowded: all the seats were taken and many were standing," she told Russian news website Gazeta.ru, according to The Telegraph.
After the explosion went off with a thundering clap followed by a strong smell and smoke, she said, passengers moved to the opposite end of wagon.
The jam caused two women to pass out.
The train did not stop while this was going on, Ms Polina said.
When survivors got out at the Technology Institute station, they saw that the carriage next to theirs was shattered, "the windows blown out, no light, blood".
A man near the blast site, Geoff Edwards, told BBC News that he saw helicopters flying around the Technology Institute station, which a colleague told him landed "to collect dead bodies".
Russian President Vladimir Putin had been in St Petersburg on Monday for a meeting with Belarussian leader Alexander Lukashenko.
He said he was considering all possible causes for the blast, including terrorism, and was consulting with security services.
In the aftermath of the blast, which was initially mistaken for two explosions, emergency services flocked to the scene and a helicopter hovered overhead.
Pictures and video footage of the injured proliferated on social media, showing casualties on the platform amid clouds of smoke.
The authorities closed all stations on the St Petersburg metro shortly after, and the Moscow metro said it was taking additional security measures.