Security footage has captured the moment a mudslide swept away a border crossing between Nepal and China today (Wednesday).

Warning:The article and the video above may be upsetting to some.

Reuters is reporting that at least nine have died and hundreds of tourists are missing after a wall of mud and rock apparently collapsed into a river on the Himalayan border between the two countries.

The verified video above is awful viewing as it shows dozens, if not hundreds, of people on the ground attempting to flee as an unimaginably large mudslide smashes into the border crossing.

The footage was taken at Gyirong Port, in the Tibetan region of China. The timestamp says it was taken at 11 a.m. local time, but reports indicate the mudslide happened at 8.30 a.m.

The Chinese People’s Liberation Army has sent a 600-strong rescue force to the disaster area as well as supplies.

Nepal’s tourism authority has said there are 386 travelers missing in the region, including three U.S. citizens and 12 British nationals.

South Korea says that eight of its citizens are unaccounted for, while 105 Indian nationals are also missing.

The cause of the mudslide remains unknown, but the German Research Centre for Geosciences has reported a 4.4 magnitude earthquake roughly seven minutes before the mudslide hit the border. Authorities are concerned about a second flood.

“With a blockage still lodged upstream on the Nepal-China border river, authorities warn a second flood ​may occur,” says Qianggong Zhang, head of climate and environmental risks, at the Kathmandu-based International Centre for Integrated Mountain Development.

“There could be heavy casualties or loss of ‌property,” ⁠district administrator Narendra Pariyar tells Reuters. “There is devastation everywhere we look,” adds Tula Bahadur BK, a health worker in Rasuwa. “The settlements next to the river have been completely swept away. Five of my own relatives are missing.”

Search operations are underway on both the Tibet and Nepal sides. The water is currently too high for helicopters to land.

This is a developing story…