Olympic tennis champion Zheng Qinwen has donated one million yuan ($150,000) to relief efforts following deadly flash floods and landslides that hit the China-Nepal border, a charity said.

Rescuers struggled on Monday through mud and debris for a sixth day, as the number of missing people soared to nearly 4,500 since tsunami-like glacial floods roared down from the China-Nepal border, creating an "unimaginable" disaster.

Rescue efforts were hampered by rain, rising river waters and the formation of a new lake near the Tibet border.

The horrific videos from the Himalayan border of Nepal and Tibet were harrowing.

A Filipino doctor who went on a pilgrimage in Nepal has gone missing following the massive flash flood that tore through the Nepal-China border this week.