Scenes of devastation in Nepal's Nuwakot district. Photo: Arun SANKAR / AFP via Getty Images

At least 1,114 people have died in Nepal and nearly 4,000 more are missing, according to Nepal's disaster agency. On the Tibetan side, the death toll stands at 16, and more than 500 people are unaccounted for, Chinese state media reports.

The UN's humanitarian agency has said the response is entering a new phase, with authorities intensifying relief and recovery operations.

In Nepal, efforts continue to rescue workers, potentially in the hundreds, believed to be trapped in hydroelectric station tunnels.

A massive flash flood, believed to have been triggered by a glacial collapse, swept through a Himalayan valley last Wednesday, wiping out villages.

Nearly 12,000 people have since been rescued, according to Nepal's disaster management agency.

But thousands more, including hundreds of foreign nationals - from India, the UK, Australia, the US, Malaysia, and more - are still missing. A week on, fears are growing that the death toll will only rise.

Chinese state media has not reported any survivors on the Tibetan side of the border, but the search continues. Beijing, which annexed Tibet in the 1950s, tightly controls the region. All information comes from state media and foreign journalists cannot travel there without permission.

Rescuers using heavy machinery, working around the clock, have been able to re-open the route to the Gyirong border crossing between Nepal and Tibet and clear the road of debris, which will accelerate the search for the missing, Chinese state media said.

Rescue operations continue in challenging conditions, and experts from China and India are helping build temporary bridges to reach remote areas. Drones are being deployed over hard-to reach areas to scan for survivors.

The UN's humanitarian agency said the main challenge is now access, with more than 40 bridges destroyed.

The most remote communities are relying on army helicopter flights for supplies, and villages are still struggling for fuel and electricity.

The full impact of the flood in Tibet is unclear. China has released information through state media outlets showing the devastation around the border, but has given few details about the victims or the impact on local villagers.

In Nepal, nearly 3,500 people have been left homeless and displaced in 27 sites - mostly schools, which disrupts education - across the districts of Nuwakot and Rasuwa.

The priority for them now is "receiving humanitarian assistance, recovering and identifying the remains of the loved ones, tracing missing relatives and reunifying separated children, and accessing psychosocial support", the UN's humanitarian agency said.

People packed into overcrowded shelters, contaminated water and damaged health facilities are putting the population at greater risk of disease in the middle of the monsoon season, the agency added.

Nepal's prime minister, Balendra Shah, said there was a renewed emphasis on protecting the lives of survivors, providing medical treatment and psychological counselling.

Nepal's government and the UN have agreed to launch a four-month humanitarian flash appeal.