Moscow (AFP) - In a small park near Moscow's Victory Park metro station, five medics huddled around a man stretched out on the grass.
"Keep talking to him, just keep talking," a female medic working quickly to stitch up a wound on his hand told her colleagues while a male doctor removed the man's shoes.
The victim of Tuesday's metro accident, who appeared to be in his 60s, breathed laboriously into an oxygen mask, his chest heaving, while an ambulance driver unfolded a stretcher to load him into the vehicle.
Twenty people died and over 100 were injured in the metro derailment in a tunnel more than 80 metres underground, the deadliest accident in the transport system's history, which transformed the normally placid, affluent Victory Park neighbourhood into a disaster scene.
Emergency workers were battling to free trapped bodies from the crumpled wreckage of the front carriage in a tunnel leading from Victory Park station, the city's deepest.
The accident came as millions of Muscovites were heading to work on the overloaded metro system that dates from the Stalin era and is famous for its ornate stations.
Over a thousand passengers had to be evacuated after the train braked abruptly and three carriages derailed. Those who could trudged through the tunnel to the nearest platform.
- Day of mourning in Moscow -
As mid-July temperatures soared to 28 degrees Celsius (82 degrees Fahrenheit), rescue workers filed in and out of the station with their heavy gear while helicopters arrived and took off, taking the most gravely injured to hospital.
Other firefighters recovered from their efforts in the shade, drinking water from fire engines parked around the busy Kutuzovsky Prospekt highway, near a large park commemorating Russia's victory in World War II.
"Right now they are cutting apart (the train carriage)," one exhausted firefighter said. "The train is at the very lowest point of the tunnel."
He denied that there had been a fire in the tunnel, saying that "people mostly broke bones. There was no fire."
Work to clear the tunnel could take 24 hours, officials said, and Muscovites will have to take replacement buses.
Moscow mayor Sergei Sobyanin announced a day of mourning for Wednesday "due to the scope of the tragedy" and vowed "not only sackings but criminal inquiries" against those responsible for what investigators said were violations.
On social networks, however, Muscovites raged against the mayor, who had fired previous metro management, blaming him for metro breakdowns over the past two years which have become more frequent despite a hike in fares.