Filipinos are assessing the damage from Friday's powerful typhoon, which is known to have killed more than 100 people while causing widespread destruction across the central part of the country.
The death toll is expected to rise, although the full extent of the damage and casualties will not be clear for some time.
Typhoon Haiyan - one of the strongest storms ever recorded - pounded the central Philippines, cutting electricity and communications while flattening buildings, uprooting trees and leaving entire communities flooded while creating landslides.
The typhoon made landfall on the islands of Leyte and Samar, creating a storm surge of 5 meters in some locations of the archipelago nation.
Nearly 800,000 people were evacuated from their homes ahead of the storm, which is known in the Philippines as Yolanda. It affected more than 4 million people across 36 provinces.
The typhoon had winds of over 300 kilometers per hour with stronger gusts as it lashed the islands.
The storm lost some strength as it headed out to sea, but could gain strength again on its way toward Vietnam where it is expected to strike Sunday.
U.S. Secretary of State John Kerry has issued a statement to let Philippine officials know the U.S. is ready to help.
Philippine meteorologists said Haiyan could be more dangerous than last year's Typhoon Bopha, which killed at least 1,100 people on the southern island of Mindanao. Bopha was the world's most powerful storm of 2012.
The Philippines is vulnerable to severe flooding caused by heavy rains and tsunamis. It is hit by about 20 tropical cyclones each year.
Presidential spokesman Sonny Coloma said the government is working to distribute relief goods and prevent mass casualties in the areas worst hit by Haiyan.
"The goods were pre-positioned there and have been brought to the areas of great concern. Right now they're taking care of continuing needs. Let's remember with those past calamities, ones similar to this, what the president wants is a timely supply and enough food."
Television images of Leyte Island's Tacloban city showed streets turned into rivers, as iron sheets from damaged buildings swirled in the air above. Many poorly constructed houses were completely washed away. The airport was badly damaged.
Minnie Portales, Public Engagement Director with World Vision Philippines, told VOA her aid group has not been able to contact its spokesperson in Tacloban. She said some areas there saw nearly 5-meter-high waves and were under 3 meters of water.
"All the electricity has been cut off, all the houses were damaged, particularly in Tacloban because of the strong winds that were 350 kilometers per hour. And there's a difficulty in terms of communication because there are two telecommunications centers that were already affected."
Portales said there will be an immediate need for food, water and shelter, since many homes and agricultural land were damaged.
The World Vision official was speaking from Manila, which was not expected to be impacted significantly by the storm.
But one area of particular concern is the central Philippine island of Bohol, where more than 200 people were killed in a 7.2 magnitude earthquake last month, forcing thousands of people to stay in temporary shelters.