A US national flag is torn down in New Orleans.-sina.com

Two cars are crushed after a side of a building collapsed in downtown New Orleans, after Hurricane Katrina hit, August 29, 2005. (Xinhua/AFP photo)

The US government on Monday declared major disasters in the two Gulf Coast states of Louisiana and Mississippi, as Hurricane Katrina plows into the region.

White House spokesman Scott McClellan told media that US President George W. Bush approved the major disaster declarations aboard Air Force One en route to Arizona, paving the way for the use of federal money to help respond to the hurricane, one of the strongest storms ever to threat the country.

McClellan said federal funds will be used for response and recovery efforts in Louisiana and Mississippi.

Hurricane Katrina bore down on the Gulf Coast earlier Monday with 233-kph winds and heavy rain, submerging some neighborhoods up to the rooflines in New Orleans, Louisiana, hurling boats onto land and sending water pouring into Mississippi's strip of beachfront casinos.

As it continues to move inland, it appeared to have spared the vulnerable below-sea-level city of New Orleans.

However, some 40,000 homes just east of New Orleans were destroyed.

Katrina hit the southern tip of Florida as a much weaker storm Thursday and has so far claimed 11 lives, leaving streets and homes flooded, and knocking out power to 1.45 million people.