Beijing
High winds and freezing rain hit participants in the race in the Yellow River Stone Forest, a tourist site in Gansu province, the state-run Xinhua news agency reported.
A total of 172 people took part in the mountain marathon.
As of 9.30 Sunday morning, the death toll rose to 21, the official media reported.
Other 151 mountain marathon participants were confirmed safe, of which eight with minor injuries were treated in the hospital.
According to the rescue headquarters, at about 1 pm on Saturday, hails, freezing rain and gales hit the area of the race's high-altitude stage between 20 to 31 km.
Participants suffered from physical discomfort due to the sudden drop in air temperature.
The race was halted when some runners went missing.
Local governments initiated an emergency response and gathered over 1,200 well-equipped rescuers to search for the missing persons, said Zhang Xuchen, mayor of Baiyin City, at the press briefing.
The temperature dropped again during the night due to the area's complex terrain and topography, making the search and rescue more difficult, the report said.
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