An expert climbing guide says a coronavirus outbreak on Mount Everest has infected at least 100 climbers and support staff.

That's the first comprehensive estimate amid official Nepalese denials of a COVID-19 cluster on the world's highest peak.

Lukas Furtenbach of Austria says his estimate is based on confirmations from rescue pilots, insurance providers, doctors and expedition leaders, among others. He spoke with The Associated Press in Kathmandu on Saturday, a week after halting his Everest expedition due to virus fears. He said he could visibly see people were sick at base camp, and could hear people coughing in their tents.

Nepalese mountaineering officials have denied there are any active cases on the country's Himalayan mountains.