Nepal has ramped up rescue efforts as it searches for thousands of people missing along its northern border with China, where a catastrophic flash flood wiped out towns and villages on Wednesday morning, killing more than 160 people.

Nepalese Foreign Minister Shisir Khanal said Thursday that thousands of families have lost their homes and remain untraced.

The National Disaster Risk Reduction and Management Authority in Nepal said 826 people are missing, with the Nuwakot and Rasuwa districts being the worst affected. The authority said 44 Nepalese Army personnel, 28 police personnel, and 13 Armed Police Force personnel are among those missing.

The Nepalese Army and private helicopters are conducting rescue missions, with about a 100 people rescued from the affected areas, spokesperson Brigadier General Raja Ram Basnet said. Army teams also rescued people trapped in the Trishuli hydropower project’s facilities.

At least eight foreign nationals were airlifted to Kathmandu by the army, he said.

Videos posted online by the army show its personnel rescuing people trapped in the thick, concrete-like mud covering many of the villages and towns that stood in the flood’s path.

China, where 558 people are missing in Tibet, dispatched 111 emergency rescuers to Gyirong Port in Xizang carrying detection, life-saving, demolition, communication, and support equipment. With roads washed away or damaged, the team was flown from Chengdu early Thursday morning, landing at Dingri Airport in Shigatse.

The People’s Liberation Army also sent a group to take over command over military rescue forces, including aviation, medical, transportation, and engineering troops.

The People’s Daily said a barrier lake has formed about 2.5 km from Gyirong Port, posing “significant challenges to ongoing rescue efforts.”

Nepal’s Khanal said about 500 foreign nationals are out of contact, many of them on pilgrimage to Mansarovar, a sacred site for Hindus, in Tibet. He said the Nepalese government has been in contact with foreign embassies on the missing foreign nationals.

“We are as committed to the safety and well-being of foreign nationals as we are to the Nepali citizens,” he said in Kathmandu.

Nepalese Prime Minister Balendra Shah and Infrastructure Development Minister Sunil Lamsal have travelled to Bidur, in Nuwakot. They will meet local officials and discuss relief and rehabilitation as well as how to restore the damaged infrastructure.

India flew in 10 tons of relief supplies to Nepal, including temporary shelters, blankets, hygiene kits, solar lamps, and medicines, on Wednesday evening. A second flight carrying medicines and food packets took off Thursday morning.

India and China have offered assistance but are waiting for Kathmandu to assess its emergency needs and raise a request as current protocols require. The US and the World Bank have also offered support.

India, China, and the World Bank are coordinating financial and other assistance for rescue and reconstruction, the Kathmandu post reported, adding the World Bank has offered to mobilize up to NPR 25 billion (about $165 billion) in emergency assistance.