At least 160 people have been killed after massive flash floods struck areas along the border between Nepal and China on Wednesday.
Police in Nepal have confirmed 157 deaths so far, while China's state broadcaster CCTV reported that three people had died.
Officials in Nepal said around 403 people, including 341 foreign nationals, are still reported missing. Sunil Sharma, a spokesperson for the country's tourism board, said 133 of those missing were Indian nationals on a pilgrimage to Mount Kailash in Tibet, a sacred site for Hindus.
The missing also include 47 people from the United States, 34 from Australia, 33 from the United Kingdom and 24 from Canada, according to Sharma.
Meanwhile, CCTV reported that 265 people were missing following a mudslide in Gyirong County in Tibet, near the border with Nepal.
Videos shared by Nepal police and others on social media showed torrents of muddy water crashing through mountain valleys in the Himalayan district bordering China.
"I witnessed the flood sweep away eight or nine trucks, along with houses and people," Suman Chalise, a 34-year-old teacher, told AFP in Nuwakot district.
"It was absolutely heart-wrenching. I had not witnessed such devastation before."
The police spokesperson said earlier that authorities did not know the extent of the damage but said they had "alerted people who are staying near the riverside to relocate."
The Nepal Army said it had deployed helicopters and disaster response personnel to the affected area.
The Nepal Electricity Authority said about 430 megawatts of production capacity, including from hydropower and solar facilities, has been damaged.
"The disaster has damaged the production, transmission and distribution facilities of the Authority...resulting in disruption of electricity supply," it said.
Sarthak Shrestha, a remote sensing and geo information analyst at the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), said a preliminary assessment showed "no anomalies" from China's side of the border.
"We believe a rock-ice avalanche occurred in Nepal, blocking the Lhende river and causing the cascading flood event," he said.
Several highways were also closed, Nepali authorities said.
Chinese state broadcaster CCTV reported on Wednesday that "a mudslide disaster on the Nepalese side resulted in major casualties and missing people at the Gyirong Port" in Tibet.
Footage shared by the broadcaster, showed rushing water carrying tree branches and debris, as well as a flooded road.
State news agency Xinhua said Chinese President Xi Jinping had urged "all-out" rescue operations, but did not provide figures on injuries or deaths.
Xi said that "the most urgent task is doing everything possible to search for and rescue the missing people...quickly treat injured people and minimise casualties to the greatest extent possible," according to CCTV.
Traffic authorities in Tibet's Shigatse said roads in the area were "at risk of mudslides and unsafe for passage" in a post on social media on Wednesday.
In July last year, 17 people went missing after a mudslide near the Gyirong Port, Xinhua reported at the time.
Monsoon rains from June to September regularly trigger deadly floods and landslides across South Asia.
