Dozens of people were confirmed dead and hundreds more are missing after a flash flood swept through remote valleys in Nepal and Tibet on Wednesday.

Nepali police said that authorities have recovered 157 bodies. Officers were "working to move families in flood-risk areas... to safer locations," police said.

"The pain and loss you have suffered is not small. But I want to assure you that you are not alone in this difficult time — the state is with you with all its means and resources," Nepal Prime Minister Balendra Shah said in a statement.

"Please be patient. The government takes full responsibility for your rescue, treatment, food and shelter. In times of such a disaster, we all need to stand together."

In China, authorities said at least three have died, with 265 still missing, China's state broadcaster CCTV ‌said.

The floodwaters washed away villages, damaged bridges and destroyed electrical infrastructure on both sides of the Nepal-China border.

"There is devastation everywhere we look," ‌Tula ​Bahadur BK, a health worker in Rasuwa district, told Reuters.

"The settlements next to the river have been completely swept away. Five of my own relatives are missing."

At the same time, Chinese authorities also reported that a mudslide caused "major casualties" on the other side of the border in Tibet.

Hundreds of people missing

Nepal's Tourism Ministry said 403 travelers were reported missing for several hours after the floods struck. 

Missing travelers included 341 foreign tourists, among them were:

• 142 people from India
• 47 from the United States
• 34 from Australia
• 33 from Britain
• 24 from Canada,
• At least 62 missing Nepali citizens

Other nationalities of those missing included people from 

• Malaysia
• The Netherlands
• Portugal
• South Africa
• South Korea

China's state news agency Xinhua reported Thursday that the number of missing people had increased to 558. State broadcaster CCTV reported that 260 of the missing people were foreigners.

Australian Prime Minister Anthony Albanese said Thursday that 34 Australians were missing following the flash flooding. 

"Our thoughts are with all those who will be concerned about their loved ones today," Albanese said.

A Nepali police spokesperson told Germany's DPA news agency that dozens of personnel were also missing.

"So far, we only have confirmation of 26 police personnel who remain missing in the flood," they said.

"We also have missing information of government revenue officials, hydropower workers among others. But we are still collecting the data."

What caused the flash floods?

Nepal's Foreign Minister Shisir Khanal said an earthquake triggered an avalanche in the Himalayas that then triggered flash floods in the valleys below.

Xinhua said a mudslide on the Nepali side of the mountains spread to Gyirong County in Tibet.

"Entire villages and market areas have been wiped out," said David Fisher, the Nepal head of the International Federation of Red Cross and Red Crescent Societies (IFRC).

Major rescue operations underway

Nepal dispatched more than a dozen rescue helicopters to the mountainous Rasuwa region, but floodwaters were too high for the helicopters to land.

Nepal's prime minister said the military and police were assisting with rescues.

"Instructions have been given ... to move ​the people living in the lower areas ⁠to safer places," Shah said. "People along the river are advised to exercise extra caution and remain alert."

Chinese President Xi Jinping also ordered an "all out" rescue effort.

He said "the most urgent task is doing everything possible to search for and rescue the missing people... quickly treat injured people and minimize casualties to the greatest extent possible," according to Chinese state media.

A second flood may be imminent, according to Qianggong Zhang, head of climate and environmental risks at the International Centre for Integrated Mountain Development.

"With a blockage still lodged upstream on the Nepal-China border river, authorities warn a second flood may occur," he told the AFP news agency.

Edited by: Wesley Dockery 

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