Two climbers have died near the summit of Mount Everest, becoming the first fatalities of the 2021 expedition, their expedition agency said on Thursday.

A Swiss and an American national died during the final ascent of the world’s tallest peak, according to Mingma Sherpa, chairman of the Seven Summit Treks, an expedition agency based in Kathmandu.

“The climbers who were members of our expedition team died during the final ascent,” Sherpa told dpa news agency on Thursday morning.

The Swiss climber had successfully reached the summit but began experiencing issues during his descent, while the American died due to snow blindness and exhaustion at Camp IV before reaching the summit, the agency wrote in its Facebook page.

Even as Nepal continues to grapple with the second wave of the coronavirus pandemic, more than 100 climbers have already reached the world’s tallest peak, while others are expected to make the final push in the next few days.

Local media, a climber as well as at least one hospital in Kathmandu have reported Covid-19 transmission among some Everest climbers, a claim which the Nepalese authorities have rejected.

Some of the successful climbers of this season so far include Bahraini Prince Mohammed Hamad Mohammed Al Khalifa and Kenton Cool, a Briton who reached the peak for the 15th time, according to the Himalayan Times.

Climbing guide Kami Rita Sherpa has improved his own world record with the 25th summit of the mountain and is expected to make one more trek to the summit before the end of the season.