America's former disaster chief Michael Brown, who became the personification of the government's listless response to Hurricane Katrina, said he told top officials of massive flooding in New Orleans on the day the storm howled ashore.
He told senators yesterday that he spread a warning in the top echelons at the White House that "we were realising our worst nightmare."
Mr Brown said he dealt directly with White House officials on the day of the August 29 storm that ripped through Louisiana, but the Homeland Security Department was also getting regular briefings.
Those he was dealing with, Mr Brown said, included President George Bush's chief of staff Andrew Card and deputy chief of staff Joe Hagin.
Administration officials have said they did not realise the severity of Katrina's damage until after the storm had passed.
Mr Brown's testimony bolsters Democratic claims that the Bush administration ignored signs that a catastrophe had been imminent.
The administration's lacklustre response to Katrina undermined Americans' confidence in Mr Bush's leadership abilities and contributed directly to a decline in his opinion poll ratings.
Under oath, Mr Brown told the Senate Homeland Security and Governmental Affairs Committee that 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," Mr Brown said about a video conference with administration officials, in which Mr Bush briefly participated, the day before Katrina hit. "Because I knew in my gut this was the bad one."
In the end, the storm claimed more than 1,300 lives, uprooted hundreds of thousands more and caused tens of billions worth of damage.