One of the strongest typhoons ever to hit land has slammed the Philippines, forcing millions to take shelter. Packing sustained winds of up to 320 km/h (199mph), Typhoon Haiyan left at least four people dead, but it may be days before the full damage is known.
The storm ripped apart buildings and triggered landslides as it ploughed across the country's central islands. Officials said more than 12 million people were at risk, but the storm's rapid passing could limit its impact.
"We expect the level of destruction caused by Typhoon Haiyan to be extensive and devastating, and sadly we fear that many lives will be lost," said Save the Children's Philippines director Anna Lindenfors.
The Philippines has experienced more than its fair share of super typhoons over the past decade, according to experts. There were at least three of these powerful events in nine of the 10 years between 2002 and 2012. The islands are unlucky, scattered along the world's most active typhoon belt where plentiful supplies of warm water and moist air provide the energy to kick start super storms.
Despite these factors, Haiyan has shown a number of unusual features which have increased its strength. Normally the walls of the storm that rotate around the eye are replaced as it moves, often weakening the wind speed. In the case of Haiyan this hasn't happened. Another factor has been the speed of this typhoon. Going so quickly, it hasn't stirred up the waters ahead of it. Slower storms churn up the waters, causing an upwelling of colder water that usually takes the energy from the storm. However Haiyan has now lost energy over land and is expected to move on to Vietnam as a Category 3 Typhoon in the next few days.
Meteorologists had earlier warned that the storm could be as devastating as Typhoon Bopha in 2012, which ravaged parts of the southern Philippines and left at least 1,000 people dead. Haiyan - equivalent to a category five hurricane - is now heading towards Vietnam and southern China.
The storm made landfall on the Philippines shortly before dawn, bringing gusts that reached 379 km/h (235 mph), waves as high as 15m (45ft) and up to 400mm (15.75 inches) of rain in places.
There were reports of buildings being ripped apart, flash floods and landslides. Schools and offices were closed, while ferry services and local flights were suspended. Hospitals and soldiers were on stand-by for rescue and relief operations.
Power and communication lines were also cut to some areas. Haiyan raged across Leyte and Samar, turning roads into rivers, and battered Cebu city, the country's second largest with a population of 2.5 million. The eye of the storm - known locally as Yolanda - passed well to the south of the capital Manila, but the city still felt its force. "The wind here is whistling. It's so strong and the heavy downpours are continuing, "said a resident to journalists.
Typhoon Haiyan is one of the strongest storms ever recorded, as Jon Donnison reports
"It was frightening. The wind was so strong, it was so loud, like a screaming woman. I could see trees being toppled down," Liwayway Sabuco, a saleswoman from Catbalogan, a major city on Samar, told AFP news agency.
A spokesperson for the British Red Cross, Nichola Jones, who is in Tagbilaran on the central island of Bohol, said the typhoon had cut power and torn off roof tiles, but was "not too bad".
"But I think to the north - that's the area that has borne the brunt. Those were the areas worst hit by the earthquake last month."
Jeff Masters, meteorology director at the private firm Weather Underground, said in a blog post that the damage from Haiyan's winds must have been "perhaps the greatest wind damage any city on Earth has endured from a tropical cyclone in the past century".
Correspondents say that, while the country is better prepared than for previous storms, it is not clear whether even buildings being used as storm shelters can withstand these winds. In its path are areas already struggling to recover from a deadly 7.3-magnitude earthquake last month, including the worst-hit island of Bohol where about 5,000 people are still living in tents.