I want news from neutral country as I am unable to buy some story that without any gunshot 20 were killed.
The harsh conditions can easily increase the death toll, even without guns involved. The high altitude means your body gets less energy for everything and the extreme cold means that you need more energy add the two and easily survivable things will kill you in your sleep.
Even just one factor, hypothermia has claimed multiple lives in a subtropical climate (Florida) were rangers in training couldn't get dry and died of the cold. In freaking florida.
(Source:
https://www.nytimes.com/1995/02/17/us/4-army-ranger-candidates-die-in-chilly-florida-swamp.html)
So even without getting shot, just getting injured in a physical fight the adverse conditions can finish you off quite nicely.
Or maybe they're hiding what hapenned to prevent war.