ASHINGTON Feb 11, 2006 (AP)— Top White House officials were warned that Hurricane Katrina would be "our worst nightmare" the day the storm roared ashore, former federal disaster chief Michael Brown says.

An assertive Brown told senators Friday that he described levee failures and massive flooding last Aug. 29 to chief of staff Andrew Card, deputy chief of staff Joe Hagin and others in the White House.

He said the Homeland Security Department was among a half-dozen government agencies that received regular briefings that day from him and other officials by way of video conference calls.

Administration officials have said they did not realize the severe damage Katrina had caused until after the storm had passed. But under oath, Brown told the Senate Homeland Security and Governmental Affairs Committee he could not explain why his appeals failed to produce a faster response.

"I expected them to cut every piece of red tape, do everything they could … that I didn't want to hear anybody say that we couldn't do everything they humanly could to respond to this," Brown said about a video conference with administration officials in which President Bush briefly participated the day before Katrina hit. "Because I knew in my gut this was the bad one."

In the end, the hurricane claimed more than 1,300 lives, uprooted hundreds of thousands more and caused tens of billions of dollars worth of damage in New Orleans and other Gulf Coast communities.