Nepal is running so desperately short of oxygen cylinders that it has even asked mountaineers on Mount Everest to bring back their empties instead of leaving them behind on mountain slopes to lighten their burden, an official said on Monday.

The country has issued climbing permits to more than 700 climbers for 16 Himalayan peaks out of which 408 are for Mount Everest in the current April-May climbing season.

The Nepal Mountaineering Association has asked the climbers to help Nepal deal with a surge in COVID-19 cases that has overwhelmed the country's healthcare infrastructure.

Kul Bahadur Gurung, a senior official with the NMA, said climbers and their Sherpa guides were estimated to have carried at least 3,500 oxygen bottles this season. These bottles often get buried in avalanches or are abandoned on the mountain slopes at the end of the expedition.

"We appeal to climbers and sherpas to bring back their empty bottles wherever possible as they can be refilled and used for the treatment of the coronavirus patients who are in dire need," Gurung told Reuters news agency.

On Sunday, Nepal reported a daily increase of 8,777 infections, 30 times the number recorded on April 9. The total caseload stands at 394,667 and 3,720 deaths, according to government data.

Many private and community hospitals in Kathmandu have said they are unable to take any more patients due to lack of oxygen. There was a shortage of both the gas and canisters.

"We need about 25,000 oxygen cylinders immediately to save people from dying. This is our urgent need," Samir Kumar Adhikari, a health ministry official said.