Updated April 04, 2017 11:13:57

Witnesses have recounted the terrifying moment a blast ripped through a train carriage travelling in an underground metro tunnel in St Petersburg, in western Russia.

At least 11 people died in the explosion, which left dozens more injured. Authorities say it's too early to know whether it was a terror attack.

St Petersburg resident Natalya Kirillova was inside the carriage and described hearing a "huge bang".

"It was deafening," she said. "Everybody fell to the right. Not down to the floor, but on seats.

"When we were climbing out the train carriage collapsed, all of it. Everything went black, it started to fall apart and while we were approaching [the station].

"I just thought oh God, please let us reach the station. And then when I looked back there were huge number of people lying on the floor."

Photo: Witnesses said people emerging from the stations looked confused. (Reuters: Anton Vaganov )

As she emerged from the carriage, Ms Kirillova saw bodies.

"It was scary. And when we left they took out several people covered in blood," she said.

"[There was] a woman, her whole face and nose — all of it was a large massive wound."

Victims were 'blackened', had their clothes burned

Anna Sventik, a St Petersburg resident, was traveling on a metro train that passed through the same station moments after the blast.

"Our train slowed down a bit, and one woman started having hysterics when she saw the people lying on the platform, blackened, in some places with no clothes, burned," she said.

"It was very scary."

Photo: Injured people were covered in blood, witnesses said. (Reuters: Anton Vaganov)

Vyacheslav, another commuter who was leaving another train on the same platform, saw the aftermath of the blast.

"A [metro] employee ran out at that interchange and asked if there are men willing to help carry dead bodies. They said that," he said.

'I'm cautious and frightened'

Ivan Filipov saw ambulances and firetrucks as he approached the metro station.

"All the people were standing there shocked. They didn't understand at all what happened," he said.

Photo: Emergency crews rushed to affected stations. (Reuters: Anton Vaganov)

He said he called people he knew to make sure they were not on the train.

"I'm cautious. And frightened too. I'm scared not for myself, but for my loved ones.

"What's really scary is the fact that this happened, it doesn't matter who did it. It happened, that's what matters."

Photo: Residents said they were fearful after the incident. (AP: Yevgeny Kurskov)

Reuters/AP

Topics: disasters-and-accidents, emergency-incidents, russian-federation

First posted April 04, 2017 10:11:18