TRISHULI, Nepal: 4,793 people are still missing in Nepal and China', as of Monday, after a massive wall of mud and rock collapsed into a Himalayan river and triggered devastating flash floods last week.

The death toll rose to 919 on Monday, as rescuers traced the thousands of people still missing.

Rescue teams in Nepal used helicopters to search for survivors and deliver emergency supplies to thousands of people who had been cut off in towns and mountain valleys. The disaster struck last Wednesday along a major road connecting Kathmandu with Lhasa in Tibet. The route is widely used by trekkers, pilgrims and other travellers.

Nepal's Prime Minister Balendra Shah travelled by road to one of the worst-hit districts, Nuwakot, to inspect the flood damage, his office said on social media.

The cause of the disaster also became clearer. The U.S. Geological Survey said an earthquake initially reported as magnitude 4.4 was actually seismic energy produced by the collapse of glacial rock and ice. A large debris flow followed the collapse.

Many of those caught in the disaster were pilgrims travelling to Kailash Mansarovar, a high-altitude religious site in Tibet that is considered sacred by Hindus and Buddhists, among others.

The U.S. State Department said it was sending a disaster response adviser to the region and would provide $500,000 in assistance.

Canada was also monitoring the situation closely. Prime Minister Mark Carney described the flooding as "absolutely devastating" in a post on X.

Security camera footage from the Chinese side of the border showed large numbers of people running away from a powerful torrent of mud, rocks and water. The flow destroyed buildings and swept away vehicles.