Updated

Top White House and Homeland Security officials pushed back hard on Monday against criticism of the federal government's response to Hurricane Katrina.

"I reject outright the suggestion that President Bush was anything less than fully involved," said White House homeland security adviser Frances Fragos Townsend.

Homeland Security Secretary Michael Chertoff said he "unequivocally and strongly" rejected suggestions that his agency was preoccupied with terror threats, at the expense of preparing for natural disasters.

Both officials spoke at a conference of state emergency management directors.

While both Chertoff and Townsend acknowledged that the federal response left much to be desired, both suggested federal officials up to Bush had been unfairly criticized in recent days.

Both clearly aimed their criticism at comments last week by Michael Brown, the former director of the Federal Emergency Management Agency.

Brown claimed he had issued repeated warnings to the White House and DHS, the day the hurricane slammed ashore, Aug. 29, that New Orleans was seriously flooding.

Bush and other federal officials have said they did not know until the next day, Aug. 30, that levees had failed.

"We cannot attempt to rewrite history by pointing fingers or laying blame," Townsend said.

Bush, who was traveling in Arizona and California the day the storm came ashore, was "highly engaged" in monitoring the storm's advance, Townsend said.

Townsend said it was Bush himself who first conceded several days after the storm — one of the nation's worst natural disasters — that "the response to hurricane was insufficient."

Disaster relief workers "were frustrated to see their efforts fall short," Townsend said.

"When that happens, there are only two choices. One, you can become bitter and lash out, trying to find someone else, anyone else to blame. And, unfortunately, we have seen some of that.

"The other option is to learn from the experience," Townsend said.

She said the White House welcomed congressional inquiries and would continue cooperating with them.

"But let's be clear about the facts," Townsend said. "As you know, President Bush was highly engaged in the preparation and response effort, beginning when Katrina was a tropical storm off the coast of Florida."

Townsend and Chertoff's strong defense of the government's response came as a congressional report blamed government-wide ineptitude for mishandling Hurricane Katrina relief.

Chertoff announced wide-ranging changes to the embattled Federal Emergency Management Agency. The changes range from creation of a full-time response force of 1,500 new employees to establishing a more reliable system to report on disasters as they unfold.