An aid agency says it has received reports that 1,200 people have been killed in only two of the six areas of the Philippines hit by Super Typhoon Haiyan.
The country's Red Cross says it has been told there are 1,000 dead in Tacloban and 200 in Samar alone.
The official death toll reached 138 by 1pm on Saturday (UK time) but there are fears many hundreds more could have died as the tropical cyclone smashed through the country with winds gusting up to 170mph.
A man walks amid shattered homes in Tacloban And there are growing fears for Vietnam which is now in the path of what has been called one of the most powerful recorded cyclones in history.
Gwendolyn Pang, Philippine Red Cross secretary general said: "An estimated more than 1,000 bodies were seen floating in
Tacloban as reported by our Red Cross teams. In Samar, about 200 deaths. Validation is ongoing."
A mother weeps beside the dead body of her son When asked how many had died in just the coastal town of Palo and its surrounding area, Energy Secretary Jericho Petilla said: "I think hundreds. Palo, Ormoc, Burauen... Carigara, they all looked the same."
Manila-based journalist Mike Cohen told Sky News: "The video images we are seeing are so gruesome we cannot show them. There are bodies piled up upon bodies in several areas.
"This is from Leyte and Samar provinces. We are still not through the other four provinces."
Children play among downed power lines Dozens, possibly hundreds, of towns and villages are thought to have been inundated with water after storm surges flooded low-lying areas, drowning many in their path.
TV pictures showed cars, trees and rubble from houses strewn across streets after they were picked up by giant waves and carried inland.
One survivor said: "We thought it was a tsunami."
Residents carry the body of a loved one "Almost all houses were destroyed, many are totally damaged. Only a few are left standing," said Major Rey Balido, a spokesman for the national disaster agency.
A British team of humanitarian experts is due to fly out to the far eastern country to help the UK Government decide what aid to send.
An appeal launched by the British Red Cross has already raised more than £100,000. US Secretary of State John Kerry said that America stood "ready to help".
Soldiers walk outside of Tacloban's shattered airport terminal About a million people who were evacuated because they were living in the typhoon's path have been returning to find out what is left of their houses.
Hundreds of thousands are said to have lost their homes.
Many of the most heavily damaged areas are still to be contacted because power and telephone lines are down, suggesting the final death toll could be much higher.
Many children became seperated from their parents and were left in tears Captain John Andrews, deputy director general of the Civil Aviation Authority of the Philippines, said he had spoken to colleagues in some of the affected areas by radio who had told him there were bodies lying in the street.
There were "100-plus dead, lying on the streets, with 100 plus injured" in Tacloban, the airport worker had told him.
Tacloban is the capital of Leyte, a large island of about two million people that suffered a direct hit from Haiyan on Friday morning when the storm was at its strongest.
A map showing the path of the typhoon and affected islands Leyte Island, about 350miles south of the capital Manila, is one of five islands that was in the path of the super typhoon.
A news team for local television network GMA reported counting at least 20 bodies in a church, 20 more at a pier and a further 11 that had been washed ashore, including one child.
An AFP photographer who reached the city aboard a military plane said large areas of Tacloban had been flattened.
Minnie Portales, a spokesman for the aid agency World Vision, said: "As we wait for early reports from some of the hardest-hit provinces, we fear for the worst. This could be very bad."
At one point before it hit land the super typhoon had been even stronger, with winds gusting up to 235mph, which made it among the most powerful ever.
Meteorologists said that it had slowed to 100mph after passing over the Philippines but could pick up strength again as it sweeps across the South China Sea toward Vietnam.
Hundreds of thousands of Vietnamese have been moved away from coastal areas as authorities prepared for Haiyan to make landfall around 10am Sunday. Millions are thought to be living in its path.
Iranian foreign minister Mohammad Javad Zarif (centre) is at the talks
The success of the original Star Wars made its characters world famous
Star Trek director JJ Abrams is directing the new film
Ofwat criticised Thames Water over delays to a sewage treatment programme 
Children have been left in tears by the typhoon in Cebu city
Residents of Legazpi city in Albay province, south of Manila
Damage to buildings in Ormoc City. Credit: Ritchel M. Deleon
Children sheltering in Cebu. Picture: Red Cross
Waves up to six metres high have been reported as a result of high winds
A closer look reveals the eye of the storm over the Philippines
A map showing the path and predicted path of Typhoon Haiyan
The scene of the arson attack
Copy of Mr Heath's family's statement
Mohamed dressed in a burka to flee the London mosque
Theresa May was 'mistaken' when she said poilce had Mohamed's passport
The Turkish-born German couple arriving at the airport
The pair on their way to the meeting
She emerges from the toilets with the baby in its carrycot
The three women managed to escape from the Cleveland house in May
The suspect changed from fun loving to quiet after a trip to Somalia
It is thought the unidentified girl may be from eastern Europe
The payday loans firm, Wonga, has 1.25 million customers
Wonga has come under attack from the Archbishop of Canterbury
The technology has been developed by Lord Sugar's Amscreen 
Another CCTV image shows the burka-clad figure, believed to be Mr Mohamed
Police are still hunting Ibrahim Magag, who absconded in December 2012
Simon Gittany 
Simon Gittany in a distressed state shortly after the incident
Survivors liberated from Auschwitz in 1945
How Mr Kempf described the items on eBay
Schindler's list failed to sell on eBay when offered for sale for £3m
The confrontation was caught on CCTV and shown on Channel 4
The row had a "devastating" impact on Mr Mitchell, according to Mr Davis
The total eclipse will be visible across large parts of Africa