Rescue workers struggled to reach ravaged towns and villages inthe central Philippines on Monday as they tried to deliver aid tosurvivors of a powerful typhoon that killed an estimated 10,000people and displaced more than 600,000.

The United Nations said some survivors had no food, water ormedicine. Relief operations were hampered because roads, airportsand bridges had been destroyed or were covered in wreckage, itsaid.

President Benigno Aquino, facing one of the biggest challengesof his three-year rule, deployed soldiers to the devastated city ofTacloban to quell looting and said he might impose martial law or astate of emergency to ensure security.

Super typhoon Haiyan destroyed about 70 to 80 percent ofstructures in its path as it tore through Leyte province on Friday,said police chief superintendent Elmer Soria. After weakening, thestorm headed west towards Vietnam.

Huge waves from one of the strongest storms ever recorded sweptaway coastal villages. Some officials likened the destruction tothe 2004 Indian Ocean tsunami.

“From a helicopter, you can see the extent of devastation. Fromthe shore and moving a kilometer inland, there are no structuresstanding. It was like a tsunami,” said Interior Secretary ManuelRoxas, who was in Tacloban, Leyte's capital, before the typhoonstruck.

“I don't know how to describe what I saw. It's horrific.”

The Philippines government and disaster agency have notconfirmed the latest estimate of the number of deaths from thestorm, whose sustained winds reached 195 miles per hour (313 km perhour) with gusts of up to 235 mph.

Soria, quoting local officials, said the estimated death toll sofar was 10,000. That could climb once rescuers reach remotevillages along the coast.

Nearly 620,000 people were displaced and 9.5 million “affected”across nine regions, the U.N.'s Office for the Coordination ofHumanitarian Affairs (OCHA) said in a statement. Local officialsobserved one mass grave of between 300 to 500 bodies in one area ofTacloban alone, it added.

About 300 people died in neighboring Samar province, said anofficial of the provincial disaster agency.

Across Tacloban, men, women and children walked carefully oversplintered remains of wooden houses, searching for missing lovedones and belongings. Not one building seems to have escaped damagein the coastal city of 220,000 people, about 580 km (360 miles)southeast of Manila.

Witnesses and officials described chaotic scenes. The city andnearby villages were flooded, leaving floating bodies and roadschoked with debris from fallen trees, tangled power lines andflattened homes.

Survivors queued in lines, waiting for handouts of rice andwater. Some sat and stared, covering their faces with rags to keepout the smell of the dead from one of the worst disasters to hitthe typhoon-prone Southeast Asian nation.

One woman, eight months pregnant, described through tears howher 11 family members had vanished, including two daughters. “Ican't think right now,” she said. “I am overwhelmed.”

U.S. MARINES ON WAY

About 90 U.S. Marines and sailors headed to the Philippines in afirst wave of promised military assistance for relief efforts, U.S.officials said. President Barack Obama said the United States wasready to provide additional aid.

U.S. aid groups also launched a multimillion-dollar reliefcampaign. One group, World Vision, said a shipment of blankets andplastic tarpaulins would arrive from Germany on Monday as a firststep in its plan to help 400,000 people.

An official of World Vision based in Cebu Province said therewere early reports that as much as 90 percent of northern Cebu hadbeen destroyed.

An aid team from Oxfam reported “utter destruction” in thenorthern-most tip of Cebu, the charity said.

The United Nations children's agency, UNICEF, said it wasrushing emergency supplies to the Philippines.

“Reaching the worst affected areas is very difficult, withlimited access due to the damage caused by the typhoon toinfrastructure and communications,” UNICEF PhilippinesRepresentative Tomoo Hozumi said in a statement.

Most of the storm deaths appeared to have been caused by surgingsea water strewn with debris that many said resembled a tsunami.Tacloban lies in a cove where the seawater narrows, making itsusceptible to storm surges.

AQUINO SENDS IN TROOPS

Aquino said the government had deployed 300 soldiers and policeto restore order in Tacloban.

Looters rampaged through several stores in the city, witnessessaid. A TV station said ATM machines were broken open.

Mobs attacked trucks loaded with food, tents and water onTanauan bridge in Leyte, said Philippines Red Cross chairmanRichard Gordon.

“Tonight, a column of armored vehicles will be arriving inTacloban to show the government's resolve and to stop thislooting,” Aquino said on Sunday.

Aquino has shown exasperation at conflicting reports on damageand deaths. One TV network quoted him as telling the head of thedisaster agency that he was running out of patience.

“How can you beat that typhoon?” said defense chief VoltaireGazmin, when asked whether the government had beenill-prepared.

“It's the strongest on Earth. We've done everything we can, wehad lots of preparation. It's a lesson for us.”

The U.N.'s OCHA said aerial surveys showed significant damage tocoastal areas with heavy ships thrown ashore, houses destroyed andvast tracts of agricultural land “decimated”.

The destruction extended well beyond Tacloban.

Officials had yet to make contact with Guiuan, a town of 40,000people that was first hit. Baco, a city of 35,000 in OrientalMindoro province, was 80 percent under water, the U.N. said.

There were reports of damage across much of the Visayas, aregion of eight major islands, including Leyte, Cebu and Samar.

Many tourists were stranded. “Seawater reached the second floorof the hotel,” said Nancy Chang, who was on a business trip fromChina in Tacloban City and walked three hours through mud anddebris for a military-led evacuation at the airport.

“It's like the end of the world.”

Six people were killed and dozens wounded during heavy winds andstorms in central Vietnam as Haiyan approached the coast, statemedia reported, even though it had weakened substantially sincehitting the Philippines.

Vietnam authorities have moved 883,000 people in 11 centralprovinces to safe zones, according to the government's website. ($1= 43.1900 Philippine pesos)

(Additional reporting by Rosemarie Francisco and Karen Lema inManila and Phil Stewart and Charles Abbott in Washington. Writingby Dean Yates; Editing by Christopher Wilson and Mark Bendeich)