The death toll from devastating flash floods along the Nepal-Tibet border has risen to 626 in Nepal, with nearly 2,000 people still missing as rescue operations enter their fourth day.

Nepalese police confirmed the latest figure on Saturday, marking a sharp increase from the previous toll of 579.

The disaster, which struck on Wednesday, swept through communities near the Nepal-Tibet border, destroying homes, roads and a major border crossing at Gyirong port.

At least seven people have also been confirmed dead on the Tibetan side of the border, according to Chinese state media, while 554 people remain missing there.

Rescue teams have faced difficult terrain, thick mud, raging rivers and unstable debris as they search for survivors.

Chinese rescuers reportedly reached Gyirong port on Friday after trekking through mountains and crossing dangerous waterways to reach the epicentre of the disaster.

A rescue team leader, Zou Mingqi, described the area as a “scene of ruins”, saying thick mud covered the area around the old border gate.

Satellite images have shown the scale of the destruction, with buildings and infrastructure along the river almost completely buried under mud, water and debris.

The United Nations said tens of thousands of households affected by the floods are in need of food and emergency drinking water. About 4,000 people have reportedly been rescued in Nepal.

International assistance is also being mobilised, with the European Union, Canada and the United States announcing aid for Nepal. The European Commission has pledged €2 million in immediate humanitarian assistance.

Meanwhile, rescue operations remain under threat from further flooding and landslides. Geological experts have warned that accumulated water and unstable boulders and debris could trigger secondary disasters.

The region is also in the peak summer monsoon and ice-melt seasons, conditions that can increase the risk of glacial collapses and landslides.

Many of those missing are foreign nationals, including tourists and pilgrims travelling to sacred sites such as Mount Kailash. India has the largest group of foreign visitors affected, while the number of Australians reported missing in Nepal has risen to 41.