By F. Brinley Bruton and Eric Baculinao, NBC News

American forces were dispatched to the Philippines as the Pacific island country struggled to cope Sunday after one of the most powerful storms in recorded history killed thousands and wreaked damage far worse than expected.

"At the request of the government of Philippines, Secretary Hagel has directed U.S. Pacific Command to support U.S. government humanitarian relief operations in the Philippines in the wake of Typhoon Haiyan," the Department of Defense said in a statement late on Saturday night.  

The first wave of U.S. force  — a team of 90 Marines and sailors — flew to Philippines on Sunday to assist with search and rescue operations and provide air support, the Marines said in a statement.

The death toll could climb as high as 10,000 on the island of Leyte alone after storm surges as high as trees and wind gusts reaching 175 mph destroyed towns and villages, said chief superintendent Elmer Soria, a regional police director.

The national government and disaster agency have not confirmed the latest death toll — a notable increase from Philippine Red Cross estimates on Saturday of about 1,000 people killed.

NBC News was unable to independently confirm these numbers.

Super typhoon Haiyan destroyed about 70 to 80 percent of structures in its path as it tore through Leyte Friday, Soria told Reuters.

An estimated 9.5 million people were affected and over 630,000 were forced from their homes and served within and outside evacuation centers, according to a Sunday report from the National Disaster Risk Reduction and Management Council (NDRRMC) of the Philippines.

The United Nations Children's Fund estimated that 1.7 million children lived in the areas that were pummeled by Haiyan. "This is not the first natural disaster to strike the Philippines recently, following the earthquake in Bohol three weeks ago, so we know how vital it is to reach children quickly," said Tomoo Hozumi, UNICEF's representative in the Philippines.

The NDRRMC has started to compile a list of the dead by names and regions — listing electrocution, drowning and falling debris as causes of death in most cases.

"We had a meeting last night with the governor and the other officials. The governor said, based on their estimate, 10,000 died," Soria said Sunday. "The devastation is so big."

The surging seas, which flattened buildings and swept away hundreds of people, resembled a tsunami, according to Reuters.

"The devastation is … I don't have words for it, it is really horrific," the country's interior minister Mar Roxas said in Tacloban, the hardest hit city. "All systems, all vestiges of modern living, communications, power, water, all are down."

Tacloban, a town of more than 220,000 people, was almost completely submerged by waves of up to 40 feet in height.

"The water was as high as a coconut tree," Sandy Torotoro, who lives near the Tacloban Airport, told The Associated Press.

Mila Ward told the AP she saw over 100 bodies on the street on her way to the airport. "They were covered with just anything — tarpaulin, roofing sheets, cardboards," she said.

"From a helicopter, you can see the extent of devastation. From the shore and moving a kilometer inland, there are no structures standing. It was like a tsunami,"said Roxas, who had been in Tacloban since before the typhoon struck the city.

Throughout Leyte, officials were struggling to cope with the number of dead.

"We have so many dead people," said Remedios Petilla, an official in Leyte. "We don't have bags, bags for the dead."

Communications were difficult and emergency crews were slowly making their way into the hardest hit areas, but some regions were still not assessable due to closed roads and power outages, contributing to the ambiguous death toll.

"There were heavy winds, heavy rains, no power, no cell phones while the storm passed," aid worker Joe Curry of Catholic Relief Services said.  

The deaths came even after officials evacuated almost 800,000 residents to emergency shelters.

"People are walking like zombies looking for food,'' Jenny Chu, a medical student in Leyte, told Reuters. "It's like a movie.''

By Sunday, Haiyan had become a Category 1 storm and continued to weaken as it brushed by the island of Hainan off the coast of China and Vietnam, The Weather Channel reported.

"The typhoon should make landfall in northern Vietnam by early Monday and may actually weaken to a tropical storm before landfall," but heavy rainfall and flooding was a concern, it said.