Two climbers have died on Mt Everest, the first fatalities of the season.
Swiss climber Abdul Waraich, 40, died near the summit after reaching the top and suffering exhaustion.
"We sent two additional Sherpas with oxygen and foods, unfortunately Sherpas couldn't save him," Chhang Dawa Sherpa, from Seven Summit Treks, said on Instagram.
American Puwei Liu, 55, reached the Hillary Step but was helped back down after he suffered snow blindness and exhaustion.
He was able to reach Camp 4 before he died late Wednesday, Chhang Dawa Sherpa said.
On average around five climbers die every year on the world's highest peak. But in recent seasons, a surge in the number of climbers has led to overcrowding that has been blamed for multiple deaths.
Eleven people died climbing the world's highest peak in 2019, and four deaths were blamed on overcrowding.
On one day, 354 people were lined up to reach the top from Nepal's southern side and Tibet's northern approach.
To ease the crowding, Nepal's tourism ministry capped the number of people who can summit the mountain per window of suitable weather.
Expedition organisers have been told to send teams up the peak strictly in accordance with permit numbers or limit the number of climbers going up at one time.
The coronavirus pandemic wiped out last year's season, but Nepal has eased quarantine rules to attract more climbers despite the difficulties of treating them if they contract the virus.
Nepal has issued 408 climbing permits this season, topping the previous record of 381 in 2019.
A city of tents hosting more than 1000 people - foreign climbers and support staff - has built up at the foot of Everest and the hotels along the trek are back in business.
The warmer weather that ushers in safer conditions for scaling Nepal's dangerous, snow-capped peaks has coincided with a deadly second wave of Covid-19 infections.
In recent weeks more than 30 sick climbers have been evacuated from base camp although only three have been confirmed as having had coronavirus.
The usual communal parties are absent this year at base camps after expedition groups were asked to keep to themselves and avoid socialising with others.
Breathing is already difficult at high altitudes so any coronavirus outbreak among climbing groups could pose severe health risks.