Commuters caught up in the Moscow underground blast have spoken of scenes of terror and panic as the explosion ripped through the train.
Surviving passengers were left injured and shocked by the blast
One woman, her face covered in blood, told Moscow's Channel One television station there were "very many victims".
"There was (panic). Everybody was shouting," she said.
"We could not open the carriage doors for a long, long time. Finally, the driver managed to open them and everybody walked out."
Passengers had to walk 2-3km through underground tunnels to get out, she said.
At Avtozavodskaya station, one of the nearest overground points to the explosion, distraught parents arrived to search for their children.
"My daughter is there!" a weeping woman in her 50s shouted repeatedly.
A nearby shop worker said a blood-spattered survivor, shaking uncontrollably, came into the store shortly after the blast at 0840 (0540 GMT) on Friday.
"He said 'give me a vodka,'" she said.
"He told us that he saw arms, legs scattered around the carriage," the worker, Lena, said. "He said it was bloody carnage."
The Russian MP for the area, Valery Draganov, was taken to the scene of the blast and said it was "horrible".
"You can hardly imagine what we saw there," he told Russian Ekho Moskvy radio.
He said body parts were scattered along a stretch of the underground line, suggesting the train must have kept moving for a short time after the explosion.
The BBC's Sarah Rainsford at Paveletskaya station says there are chaotic scenes, with blood-soaked stretchers on the streets, fleets of ambulances and other emergency vehicles, and helicopters hovering overhead.
"There are crowds of people milling around, trying to absorb what has happened," she said.
A Reuters staff member at the scene, Nikolai Isayev, said he saw some of the injured being taken away.
"One had a head wound and another was apparently unconscious," he said.
"The injured are being loaded into emergency vehicles and being driven off."
Rescuers fought to bring people to safety, but said there were many dead. Estimates of the number of dead and injured rose steadily in the hours after the blast.
The survivors are suffering from injuries including broken bones, smoke inhalation and burns.