Rescuers were trying to find trapped workers in hydroelectric plant tunnels on Monday after catastrophic flooding in Nepal and Tibet killed at least 900 people and left more than 4,700 missing.

In Nuwakot, one of the worst-affected Nepali districts, helicopters have been delivering food, clothes and supplies to cut-off communities while ferrying survivors and the injured out of flood-hit areas.

In Kathmandu, the walls of Tribhuvan University Teaching Hospital are now covered with posters bearing the faces of the missing, as families wait for news of loved ones swept away when the floodwaters surged through.