WASHINGTON, Aug. 31 (Xinhuanet) -- An overwhelming crisis continues to unfold in the US Gulf Coast region Wednesday as hundreds were feared dead and tens of thousands of houses were destroyed under the wrath of Hurricane Katrina.

    The most affected three states of Louisiana, Mississippi and Alabama, which had been hit by 300-kph winds Monday, are suffering from floods. electricity supply to 2.3 million people there has been cut off.

    The disaster brought memories to Hurricane Camille, which claimed 256 lives in the same region in 1969.

    As US TV news footage showed, severe floods caused by the hurricane dislodged coffins from grave yards and dead bodies floated in the water in the affected areas.

    The number of casualties is bound to rise further and the overall damage of the deadly hurricane may exceed 20 billion US dollars.

    On Tuesday, US President George W. Bush called on all Americansto help the victims of the hurricane.

    He said US citizens should help the victims of the hurricane through making donations to several aid agencies, and he gave the names of some of these aid agencies.

    "The federal, state and local governments are working side by side to do all we can to help people get back on their feet," Bushsaid, "and we have got a lot of work to do."

    The White House said the president will shorten his vacation bytwo days and head back to Washington on Wednesday to coordinate relief efforts. Some 7,500 National Guards have been assigned withsearch and rescue works in the affected region, removing debris of buildings and restoring power supply.

    Millions of people have been evacuated, but they will be unableto return to their homes for a long time.

    US officials said the damage could be worse Wednesday as flood waters continue to rise.

    Louisiana State Governor Kathleen Blanco described the crisis as "greater than our worst fears."

    "It is just totally overwhelming," he said.

    In News Orleans, Louisiana, flood waters are spilling slowly into the low-lying cities as looting broke out in some areas and gas leaks fueled fires.

    "Over the next 12 to 15 hours, water will rise, " Mayor Ray Nagin told media late Tuesday," and "we probably have 80 percent of our city under water."

    Nagin said he did not have a casualty toll from Hurricane Katrina but "there are dead bodies floating in the water."

    "This is our tsunami," said AJ Holloway, mayor of the devastated resort city of Biloxi, Mississippi, where a tidal surge swept away bridges, sent boats crashing into buildings and floodedentire neighborhoods.

    At least 50 people were known to have been killed in Biloxi alone, about 30 of them in a single apartment complex demolished by the storm.

    US insurance companies estimated that Hurricane will cause up to 25 billion US dollars in insured losses, which means the deadly storm could be the most expensive one in the country's history.

    Meanwhile, oil prices raced to the historic level of 70.85 dollars per barrel with anxiety over damage to US facilities in the Gulf Coast.

    Responding to the situation, US officials said Wednesday that the US government has decided to release oil from its petroleum reserves to help refiners affected by the hurricane.

    A formal announcement is expected later in the day.

    By midday Tuesday, Hurricane Katrina was downgraded to a tropical storm with winds around 56 kph.

    The hurricane made its first landfall on US soil last Thursday before sweeping through the US Gulf Coast region with winds up to 300 kph earlier this week. Enditem