Laura Bicker
China correspondent

Water levels in the lake which formed amid the debris of the landslide in Tibet are rising once again, according to Chinese state media.

There is a continued risk of secondary mudslides or landslides, the report adds.

The command team in charge of rescue efforts around Gyirong port, the main land border between Nepal and Tibet, have launched drones and set up observations posts to monitor the slopes and provide an early warning system to rescuers working nearby.

Search teams are making the most of a short weather window to try to find survivors.

Work is also underway to try to re-open the road.

Image source, Reuters

The death toll in Nepal has risen to 626, according to local police.

That's a significant jump from the last update of 579 dead, with almost 2,000 people still missing.

International aid agencies and various governments have stepped up emergency relief efforts amid reports that nearly 2,000 people are still missing after devastating floods in Nepal.

Countries including the European Union, Canada, and the United States have announced that they will send aid materials or financial assistance to Nepal.

According to a United Nations spokesperson, tens of thousands of households are in need of food and emergency drinking water.

According to Nepali officials, about 4,000 people have been rescued, while more than 500 have been confirmed dead.

China has also confirmed seven deaths, with more rain expected, making rescue and search operations more difficult.

Laura Bicker
China correspondent, reporting from Beijing

Image source, CCTV

New footage from Chinese state media reveals the scale of the destruction on the Tibetan side of the border. Rescue teams are shown wandering in a wasteland of mud and rock while calling out - "anyone there?"

They finally reached the land border on Friday afternoon after trekking over mountains, scaling cliff faces and crossing raging rivers to get to Gyirong port, the epicentre of the disaster in Tibet.

“It was scene of ruins,” Zou Mingqi, a fire and rescue team leader from Lhasa told the state broadcaster CCTV.

“The area around the old border gate was covered in thick mud, and your feet would sink into it when you stepped on it.”

Gyirong port was one of the main crossing points for tourists and traffic travelling between Nepal and Tibet.

Satellite images appear to show that it has been completely flattened.

At least 554 people are missing in the area and 7 people are confirmed dead.

Image source, CCTV

Image source, CCTV

Image source, CCTV

With debris and water having built up in the wake of Wednesday's devastating flash flood, rescuers on the ground face a "difficult situation" amid risk of another flood in the coming days, according to a geological expert.

Dr Alena Giesche, a geologist with the US Geological Survey, tells the BBC at least one of the areas that accumulated debris from the initial flow already appears to be releasing some water.

"People are working in these same hazardous regions and facing that risk posed by further debris and mud and the boulders that were dislodged on the ground and could still be unstable," she says.

Gieche adds that while the flash flood was a large event, it is not unprecedented, especially with the landscape of the Himalayas being "inherently unstable".

"It's also peak melt season for the ice and peak summer monsoon season," she says, citing two known triggers for glacial collapses and landslides that are exacerbated by rainfall.

Image source, Getty Images

If you're just joining us, rescue efforts have entered their fourth day after the seismic flash flood along Nepal and Tibet's border, with almost 2,000 people still missing.

Here are the latest developments:

• The official death toll in Tibet has risen to seven, with 554 people still missing, according to Chinese state media. It's unclear whether these figures overlap with those in Nepal, where more than 570 people have died and at least 1,900 are missing.
• European Commission President Ursula von der Leyen has announced Europe is committing €2m (£1.7m) in immediate humanitarian aid for Nepal, saying the support will deliver "life-saving assistance to families and communities hit hardest".
• Chinese President Xi Jinping has extended his condolences to his Nepalese counterpart, Ram Chandra Paudel, saying: "I am confident that the people of both countries will surely join hands to overcome this disaster as soon as possible and rebuild their homes."
• Satellite images taken before and after flood reveal the dramatic scale of the disaster, with previously colourful buildings lining the river along the Nepal-Tibet border now almost entirely engulfed by mud, water and debris.
• The number of Australians missing in Nepal has now risen to 41, according to a government minister - an increase from the 39 people reported on Friday.

As we've been reporting, many tourists missing in Nepal and Tibet had travelled to the region on pilgrimages.

The area is a popular site for Hindus and Buddhists, with tens of thousands visiting each year on trips to sacred sites.

Indian nationals, several of whom were on pilgrimage, form the largest group of foreign visitors affected by the flash floods.

Many Indian tourists travel through Nepal to Tibet's Mount Kailash, a 6,400 metre (21,000ft)-tall peak that holds sacred significance for Hindus, Buddhists and Jains.

Image source, Future Publishing via Getty Images

Deepak and Madhu Ahuja, who travelled from the US to Mount Kailash, are among the many pilgrims who went missing.

"We just love them a lot and want them to come home," their daughters told the BBC.

Nepal is not only a popular destination for pilgrims, it also draws hikers from around the world.

Rasuwa, the north-central region hit hardest by the flood, is a hiking hotspot. While August is not peak season, authorities believe some hikers were present when the flood struck.

There has been a steady stream of information from authorities since flash floods devastated parts of Nepal and Tibet on Wednesday. But in Nepal, where we are able to gather the most information, there have been conflicting reports.

The number of casualties and people missing following the flash floods has been updated several times, and differing numbers have been reported by the Nepalese police and the country's national disaster authority.

As efforts to rescue survivors, search for the missing and recover bodies continue, figures are being constantly updated, and it is highly likely that some numbers don't match due to the speed of the emergency operation.

It's hard to know what is happening in Tibet - it was annexed by China in the 1950s and is one of the most strictly controlled regions governed by the country. It is difficult for media to gain entry, so we rely on Chinese national media for updates, our China correspondent explains.

Simon Atkinson
Australia reporter

The number of Australians missing in Nepal has now risen to 41, according to a government minister - an increase from the 39 people reported on Friday.

One of those who was unaccounted for, 25-year-old Cara Severino, has now made contact with their family. She was hiking in a different area to the disaster zone.

Among those still missing is 46-year-old Reshma Patel from Newcastle in New South Wales. She was one of 11 Australians making a pilgrimage to Kailash Mansarovar temple with the Isha Foundation.

According to her friend Chin Valsan, Reshma’s last known location was the Tibet-Nepal border around 10 minutes before the impact.

“Family and friends have been unable to reach her and are deeply concerned for her safety,” Dr Valsan wrote on a Facebook page.

Her husband Bhavin Patel has flown to Nepal to await news of his wife.

Image source, Chin Valsan via Facebook

Aerial images of towns and villages on the Nepal-Tibet bored taken before and after floods and mudslides left hundreds dead and thousands missing capture the scale of the disaster.

In these images taken via satellite last month, the colourful buildings of Timure, Nepal, can be seen lining the river. Now, only a few remain and the area has been almost entirely enveloped by mud, water and rock.

Image source, Vantor/Handout via REUTERS

Image source, Vantor/Handout via REUTERS

The Rasuwagadhi Hydropower Plant which sits on the Trishuli River. Days ago, it was a thriving industrial site. Now, virtually no trace of it visible from the air remains.

Image source, Vantor/Handout via REUTERS

Image source, Vantor/Handout via REUTERS

Image source, Getty Images

Chinese President Xi Jinping has extended his condolences to his Nepalese counterpart, Ram Chandra Paudel.

"I am confident that the people of both countries will surely join hands to overcome this disaster as soon as possible and rebuild their homes," Xi told Paudel on Friday, China's mission to the UN said.

Chinese state media said earlier that seven deaths have been confirmed and hundreds more are still missing. Here's more on why its hard to gauge the scale of the impact in Tibet.

Authorities in China, which controls Tibet, have warned heavy rain could complicate rescue efforts over the weekend.

Image source, Weibo

The official death toll in Tibet has risen to seven, with 554 people still missing, according to Chinese state media.

The number of people dead is expected to rise significantly as rescue efforts continue.

It's also still unclear whether these figures overlap with those in Nepal, where more than 570 people have died and at least 1,900 are missing.

Laura Bicker
China correspondent, reporting from Beijing

Image source, Reuters

The dramatic footage was almost impossible to miss. A torrent of water tearing through Gyirong Port, one of the main border crossings between Nepal and Tibet, sweeping away all in its path as hundreds of people fled for their lives.

The scenes, captured by CCTV cameras, quickly spread on social media and onto screens around the world.

Except here, in China.

Only a single still-frame shot has been broadcast so far by the country's state-run flagship news bulletin.

It has also been difficult to find the video on China's heavily censored internet. It is just as hard to even find posts describing the flash flooding that has claimed hundreds of lives, with just as many still unaccounted for since Wednesday.

Beijing has launched a massive rescue operation involving hundreds of emergency workers, which is continuing, and President Xi Jinping chaired an emergency meeting with officials to co-ordinate efforts.

But when you compare the country's internet content to what much of the world has been seeing online these past few days, China's firewall becomes more visible than ever.

Read more on how the floods are being presented in China here.

Image source, Reuters

European Commission President Ursula von der Leyen has announced Europe is committing €2m (£1.7m) in immediate humanitarian aid for Nepal, saying the support will deliver "life-saving assistance to families and communities hit hardest".

The US embassy in Nepal also says it sent an initial shipment of emergency supplies, including more than 2.5 tonnes of food and supplies for two schools being used as shelters in Rasuwa.

Canada's minister of foreign affairs has announced C$5m (£2.7m) of support and New Zealand says it will contribute NZ$1m (£436,800) to the Nepal Red Cross Society and another NZ$1m to other aid groups.

India's external affairs minister says a third flight carrying 10 tonnes of humanitarian assistance has left the country, while 11 doctors, paramedics and a reconnaissance team for tunnel rescue operations have also been sent.

The International Federation of Red Cross and Red Crescent Societies said earlier it had mobilised "its entire global network", having also launched an emergency appeal for CHF 25m (£23m; $31m) to support the "immediate lifesaving response".

Freya Scott-Turner
Live reporter

Image source, Getty Images

It's now 03:30 in Nepal and 5:45 in Tibet - almost three full days since floods first hit the area on Wednesday morning. Here's the latest:

Death toll rises

• In Nepal, more than 570 are known to have died and at least 1,900 are missing, the disaster relief agency says
• In Tibet, at least five people have been killed and more than 550 are missing, Chinese state media reports. It's not clear if there are any overlap in these figures

Challenging rescue efforts

• Nepali officials say that around 4,000 people have been rescued there. Separately the tourism board reports that more than 100 tourists have been found
• But the destruction of key infrastructure like roads and bridges is making reaching the worst-hit areas incredibly challenging. Heavy rain since the flash floods has added to the challenge

Fears of a second flood

• China temporarily paused rescue efforts over fears that a lake - which formed in the aftermath of Wednesday's flooding - could burst, triggering further flooding.
• Searches have since resumed, but the Chinese military has warned more rain forecast over the weekend could further complicate rescue efforts and "mudslides may occur in some areas".

Image source, Reuters

George Graham of Save The Children UK says the charity's team in Nepal has been "working flat out" to rescue children, many of whom are stranded without their parents.

He tells the BBC News channel there are around "fifty children that we know of who are trapped in schools" who "may or may not have clean drinking water".

"The bridges that connect those schools to the roads have been washed away. The race is on to try and find those kids," he says.

"The flood came at the start of the school day," he says. "These children walk a long way from their homes to go to school, completely separate from their families."

Graham says they have rescued nine children so far who "walked a long way until they found our relief teams".

"They found themselves alone.. having to work out how to stay alive and stay safe," he says. The next job is working to reunite them with their families.

But there are "hundreds and hundreds of kids in this situation", he says.

Image source, Reuters

We can now bring you more on ongoing rescue efforts taking place near Gyirong Port, located on the Nepal-Tibet border.

China's state broadcaster CCTV reports six personnel from the Tibet fire and rescue service as well as 15 people and a dog from the Sichuan fire and rescue service arrived at the site approximately 16:30 local time (09:30 BST) on Friday.

"There was no road... it was all virgin forest and sheer cliffs," rescue worker Zou Mingqi tells Reuters, adding: "As far as the eye could see, there was nothing but ruins."

CCTV says rescue teams traversed dense forest and canyons to approach the area.

China's armed forces earlier said heavy rain scheduled to continue in Gyirong county over the weekend means "mudslides may occur in some areas".

We've continued to hear stories of loss and devastation today as relatives of those caught up in the disaster await news, and rescuers and healthcare professionals continue their response work.

These are some of the stories we've heard:

• At a rescue centre in Nepal, a woman cradling a crying child told the BBC her father, husband and mother all went missing in the floods
• Vikram Kolagatla, who is trying to find out if his wife Geetha Reddy survived the floods, said: "We’re not sure what to do. I have two little girls... [they] still don’t believe it"
• "I haven't seen this kind of disaster in my life," Nepalese army spokesperson Brigadier General Rajaram Basnet said

• Naresh Goyal, whose sister is among the British nationals missing, said it was her sister's dream to travel to Nepal and take part in the Kailash Mansarovar Yatra pilgrimage
• A doctor in Kathmandu told the BBC he treated an eight-year-old boy who had been at school when the floods hit - the rest of his family at home were swept away

• Aid worker Dhruba Gurmachhan said the situation on the ground in Nepal is "chaos" but says "there is hope" that some still missing could be found alive

Pria Rai
Outside Source presenter

Image source, Tashi Bista

Among the sheer devastation caused by the floods, Nepalis are banding together to pull their communities through.

Over the past day or so, I've have spoken remotely to a number of people supporting those in need, but one story has stuck with me in particular.

Rabi, a resident of capital city Kathmandu, tried to get as close to the affected areas as possible in order to deliver food and medicines.

He spoke to me about providing help to a woman who was already homeless and living in a tent before the flood hit. Rabi recalled how she cried and pleaded with him for any kind of assistance. He then provided some food and medicines to her.

And then there's Tashi, a wildlife filmmaker from Mustang in north-west Nepal who was travelling to and from Kathmandu. He was asked by authorities to use his drones to help map the disaster zone and use thermal imaging to find any trapped people.

"We saw that the entire town of Timure was completely covered by mud and debri," Tashi who travelled from Kathmandu said.

"We saw there were six to seven houses remaining that were on the hillside."

Although Tashi was able to help the authorities gauge the extent of the devastation, he was unable to detect any individuals in need of rescue.

This is because he regularly had to move his drone at the path of rescue helicopters. The rainy conditions and mountainous landscape also made the task difficult.

Image source, Getty Images

The UK government is deploying a rapid deployment team to Nepal to assist those affected by the flash flooding, Ed Miliband has announced.

The foreign secretary says the team will work alongside British embassy staff and local authorities, adding that Foreign Office teams will "continue to work around the clock to support British nationals and their loved ones".

He urges Brits in Nepal or China who require consular assistance to contact the British embassy in their respective country or call the FCDO hotline.