The deaths were confirmed by an official of Nepal's tourism department.

Three Indian climbers, two women among them, died of exhaustion while descending the slopes of Mount Everest, Nepali officials said on Friday, taking to 15 the total of mountaineers killed or missing in this year's climbing season.

More than 120 climbers scaled the world's highest mountain on Thursday, but some of them were caught in the crowd of people on the slopes, leading to exhaustion, dehydration and death, they said.

Nihal Ashpak Bagwan, 27, from Pune and Anjali Sharad Kulkarni, 54, from Mumbai, died on the way down from the summit, 8,850 metres high.

"Bagwan died of dehydration, exhaustion and tiredness after being caught in the jam of climbers," said Keshab Paudel of the Peak Promotion hiking agency that handled the climber's logistics.

Lhakpa Sherpa of another agency, Arun Treks and Expeditions, said his client, Anjali Sharad Kulkarni, died of weakness while coming down to Camp IV on the South Col of Everest.

The deaths were confirmed by Mira Acharya, an official of Nepal's tourism department.

Mira Acharya added that 49-year-old Kalpana Das, from Odisha, also died on Thursday during the descent from the peak, but the exact cause of death was unclear.

The deaths take to six the number of dead or missing climbers on Mount Everest in the past week. Nepal has issued permits to 379 climbers on Mount Everest in the season, which ends this month.

Hiking officials say between five and ten climbers die on Mount Everest in an average climbing year.

A total of 15 climbers have died or are missing on different Himalayan peaks in Nepal, seven of them Indians, since the start of the climbing season in March.

A Swiss climber identified only as Ernst died at 8,600 m on the Tibetan side of the mountain on Thursday, according to Everest blogger Alan Arnette, who cited a Swiss operator, Kobler & Partner.

"The winds have returned, plus the routes are extremely crowded on both sides, due to few summit weather windows this spring," Arnette said on his blog.