Survivors root through the splintered wreckage of their homes searching for loved ones who may be buried beneath. Others are scrambling to find food and water in areas littered with corpses.

Three days after Super Typhoon Haiyan, one of the strongest storms in recorded history, scythed across the central Philippines, people here are struggling to grasp the enormity of what they have lost and the challenges they face.

The storm, known as Yolanda in the Philippines, has left devastation on a monumental scale in its wake.

Thousands of houses have been obliterated. Many areas are still cut off from transport, communications and power. Some officials say that as many as 10,000 people may have been killed.

"There are too many people dead," said Richard Gordon, chairman of the Philippine Red Cross. "We have bodies in the water, bodies on the bridges, bodies on the side of the road."

Amid the carnage, hundreds of thousands of survivors are trying to cope with a lack of water, food, shelter and medicine. Aid workers and government officials are battling to get emergency supplies to hard-hit areas cut off by fallen trees and power lines.

'Worse than hell'

In Tacloban, a city of more than 200,000 that suffered a catastrophic blow from the typhoon, dead bodies still lay by the side of the road Monday.

Some had been covered by sheets or tarpaulins. But others remain where they had fallen, a look of horror frozen on their faces.

Aid workers are worried the grim abundance of corpses will create health risks for survivors, who are drinking water from underground wells without knowing if it's been contaminated.

Magina Fernandez, who was trying to get out of Tacloban at the city's crippled airport, described the situation there as "worse than hell."

"Get international help to come here now -- not tomorrow, now," she said, directing some of her anger at Philippine President Benigno Aquino III, who toured some of the hardest-hit areas Sunday.

Tacloban was shattered by Haiyan, whose tremendous force brought a wall of water roaring off the Gulf of Leyte. The storm surge leveled entire neighborhoods of wooden houses and flung large ships ashore like toys.

"I have not spoken to anyone who has not lost someone, a relative close to them," said Tacloban Mayor Alfred Romualdez, who narrowly escaped death during the storm's fury. "We are looking for as many as we can."

Difficult to assess death toll

But Tacloban is far from the only devastated area. Authorities are trying to establish the level of destruction elsewhere along Haiyan's path.

"It's not just Tacloban; it's all the coastal areas" in that region, said Gordon of the Red Cross.

Fishing communities stretch for miles down the eastern coast of Leyte, the island where Gen. Douglas Macarthur led U.S. troops ashore in 1944 at the start of the long, bloody fight to retake the Philippines from the Japanese during World War II.

The other settlements along the coast are likely to have suffered a similar fate to Tacloban's.

Across the Gulf of Leyte lies Samar, where Haiyan made its first of six deadly landfalls in the Philippines on Friday. Government and aid officials say they are still trying to reach many affected communities on that island.

A similar challenge exists farther west, on the islands of Cebu and Panay, which also suffered direct hits from the typhoon.

The death toll, as reported by the Philippine Armed Forces Central Command, stood at 942 Monday night. But with so much about the storm's impact still unknown, a full accounting of its victims will take time.

"We can give you estimates right now, but none of it will be accurate." Gordon said.

U.S. Marines join relief efforts

As the United States, the Vatican and Spain, among other nations, sent aid, Aquino declared a "state of national calamity," which allows more latitude in rescue and recovery operations and gives the government power to set the prices of basic goods.

Authorities are funneling aid on military planes to Tacloban's airport, which resumed limited commercial flights Monday. As aid workers, government officials and journalists came in, hundreds of residents waited in long lines hoping to get out.

Among those arriving Monday were U.S. Marines, sent in to assist in relief efforts.

"We're working hand in hand with the Philippines, both with their armed forces and the national police, and we will help them in their need," Brig. Gen. Paul Kennedy said.

The Marines are the "forward edge" of a broader U.S. effort to aid the Philippines, he said.

But with the airport nine miles (15 kilometers) from the city center and many roads still clogged with debris, getting supplies to where they're most needed is proving difficult.

Authorities try to control looting

The problems are the same in other stricken regions.

"The main challenges right now are related to logistics," said Praveen Agrawal of the U.N.'s World Food Program, who returned to Manila from the affected areas Sunday. "Roads are blocked, airports are destroyed."

The need for food and water has led to increasingly desperate efforts. People have broken into grocery and department stores in Tacloban.

Local businessman Richard Young said he and others had formed a group to protect their businesses.

"We have our firearms, we will shoot within our property," he said.

Authorities have sent police and military reinforcements to try to bring the situation under control.

Another dire scene played out in the city's only functioning hospital over the weekend. Doctors couldn't admit any more wounded victims because there wasn't enough room. Some injured lay in the hospital's cramped hallways seeking treatment.

"We haven't anything left to help people with," one doctor said. "We have to get supplies in immediately."

Complicating the search efforts is the lack of electricity in many parts of the storm's path.

The northern part of Bogo, in the central Philippines, suffered a blackout Sunday, and authorities said it will take months to restore power.

Storm moves onto Vietnam

Meteorologists said it will take further analysis to confirm whether Haiyan -- with gusts of more than 250 kph (about 155 mph) -- set a record.

After leaving the Philippines, the storm lost power as it moved across the South China Sea over the weekend.

Early Monday, it hit the coast of northern Vietnam, where authorities had evacuated 800,000 people, according to the United Nations. It weakened to become a tropical storm as it moved inland.

Five people were reported dead, according to the state-run Vietnam News Agency.

Aid workers said Vietnam was likely to avoid damage on the scale suffered by the Philippines. But officials have warned the heavy rain brought by Haiyan could cause flooding and landslides in northern Vietnam and southern China.

For the devastated areas of the Philippines, the bad weather may not be over. The national weather agency, Pagasa, said Monday a tropical depression was moving toward the southern part of the country.

Far weaker than Haiyan, the weather system is likely to affect mainly the islands of Mindanao and Bohol, which didn't suffer direct hits by the typhoon. But it could bring wind and heavy rain to Tacloban and the surrounding area, making conditions even more hazardous.

Aid workers said the recovery from Haiyan will take many months.

"This disaster on such a scale will probably have us working for the next year," said Sandra Bulling, international communications officer for the aid agency CARE. "Fishermen have lost their boats. Crops are devastated. This is really the basic income of many people."

Paula Hancocks and Ivan Watson reported from Tacloban; Jethro Mullen reported and wrote from Hong Kong. CNN's Andrew Stevens, Kristie Lu Stout, Aliza Kassim, Kevin Wang, Jessica King, Pedram Javaheri, David Simpson and Yousuf Basil also contributed to this report.