KATHMANDU — Catastrophic flooding and landslides on the Nepal-Tibet border unleashed waves of water and debris that have killed at least 160 people and left hundreds more missing.

Here is what we know so far: The exact sequence of events is still unclear, but yesterday morning, torrents of water and debris crashed downstream on both sides of the border.

Surveillance video from the Chinese side showed a wall of mud and water crashing over a building as terrified people ran away.Hundreds missing, many dead 

At least 165 people have been reported dead, 162 in Nepal and three in Tibet.

Chinese authorities have said the disaster caused “major casualties” and reported another 558 missing — 260 of whom are foreigners.

On the Nepalese side, authorities said today that 468 tourists, 393 of them foreigners, were unaccounted for.

The missing include Indians and others from Ukraine, Malaysia, the UK, South Africa and elsewhere.

Australia said 34 of its citizens were missing in Nepal.

Another 93 Nepalese citizens have also been reported missing.

In Nepal, a surge of water hit villages and towns on the path of two rivers — Bhote Koshi and Trishuli.

The disaster was intially described as a flood on the Nepalese side, and a mudslide by Chinese authorities.

Promises of aid and assistance came in soon after reports of the scale of the disaster.

The US has pledged US$500,000 (RM2.01 million) in emergency assistance, and the International Federation of the Red Cross and Red Crescent Societies released US$1.4 million.

“The priority now is to reach affected communities and get assistance to people who have lost their homes, suffered injuries or have been cut off,” its Nepal head David Fisher said.

The European Union said it had activated its Copernicus satellite surveillance system to help recovery efforts and was ready to provide more help, while the World Health Organisation said it had dispatched emergency medical supplies.

Neighbouring India has sent an initial 10 tonnes of humanitarian assistance.