A rush hour collision between two subway trains in Beijing has left 102 people with broken bones, Chinese state media reported.
More than 500 people were sent to hospital after the incident, which occurred at about 19:00 local time (11:00 GMT) on Thursday.
The trains collided during heavy snowfall while going downhill on the Changping subway line.
As of Friday morning, 423 people have been discharged from hospital.
While such accidents are not common on the Chinese capital's transport network, snowstorms reportedly led to slippery tracks.
This then caused a "signal degradation" which led the first train to brake suddenly, China Daily reported, citing Beijing transport authorities.
The following train was unable to brake in time while coming down the icy tracks, causing it to slam into the rear of the first train.
The impact caused the last two carriages of one of the trains to detach. It is unclear which train was decoupled.
Images and footage posted online show commuters crowded in carriages, left in the dark due to power cuts. A few were seen using emergency hammers to smash out windows for some fresh air.
In a clip posted on Chinese social media network Weibo, a woman who appears to have fainted is seen lying across several train seats.
Sixty-seven people remain in hospital for treatment, while 25 are "under observation", reports said. There were no deaths.
The incident sparked furious comments from Chinese netizens. Some were shocked by the number of injuries, while others lamented the inconvenience caused by the collision.
"Does Beijing Subway have no maintenance staff? No routine inspection?... Are we taking the lives of hundreds of people too lightly," wrote a Weibo user. Beijing Subway, owned by the municipal government, operates the 27 subway and rail lines that run through the city.
Beijing Subway apologised for the incident, adding that the company will cover the medical bills of those injured.
Given the current "extreme weather", the operator has also instructed that trains traveling above ground be driven in manual mode and for intervals between trains to be widened. The section of the subway line affected by the incident - spanning three stations - was closed on Friday.
Road, rail and air transport have all been disrupted by snowfall in Beijing.
Temperatures are expected to plummet across northern China in the coming days.
Meteorological authorities warned that temperatures will fall by 8C to 12C in most parts of the country from Thursday through Sunday. This means the temperature in Beijing could dip below -20C over the weekend.
In some cities, authorities have shut schools and suspended train services.
