The Government Accountability Office also found that the government still lacks sufficient plans and training programs to prepare for catastrophic disasters like the Aug. 29 storm that devastated much of the Gulf Coast area.
Responding, a Homeland Security Department spokesman attacked the GAO's preliminary findings as "premature and unprofessional."
The GAO report, which marks the first congressional conclusions about the much-criticized federal response to Katrina, offered a harsh assessment of the government's preparations and reaction to catastrophic disasters. It also singled out Chertoff in several shortcomings.
The GAO report said that neither Chertoff nor any of his deputies in the disaster area acted as President Bush's overall storm coordinator, "which serves to underscore the immaturity of and weaknesses relating to the current national response framework."
Leadership "was unclear," the report found.
Because of the internal confusion, federal officials were indecisive and slow to realize Katrina was a catastrophic disaster, it said.
The report also noted that Chertoff declared Katrina an "incident of national significance" on Aug. 30, a full day after the storm hit. But Chertoff did not specifically classify the storm as a catastrophic disaster, which would have activated parts of the National Response Plan to trigger a faster response.
"As a result, the federal response generally was to wait for the affected states to request assistance," the report found.
Homeland Security spokesman Russ Knocke said the GAO's findings were riddled with errors, particularly in its criticism about whether declaring Katrina a catastrophic disaster would have speeded up relief efforts.
He said federal officials and supplies were already in the Gulf Coast before Katrina hit, and that an index in the response plan that deals with catastrophes is only used for unexpected disasters.
The report, Knocke said in a statement, "is premature and unprofessional. Apart from its obvious errors, it displays a significant misunderstanding of core aspects of the Katrina response that could have easily been corrected in the most basic conversations with DHS leaders."
The report was a stinging slap to the Homeland Security Department, which oversees the Federal Emergency Management Agency and issued the National Response Plan last year.
The report by GAO, Congress' investigative arm, was presented to a special House inquiry of the government's response to the storm. The committee, chaired by Rep. Tom Davis, R-Va., is expected to release its own findings by Feb. 15. Additionally, a Senate panel will conclude a separate investigation by mid-March, and the White House is completing its own review, conducted by homeland security adviser Frances Fragos Townsend.
The Senate Homeland Security and Governmental Affairs Committee is holding hearings Wednesday at which New Orleans Mayor Ray Nagin is testifying. "We were in the most desperate need for assistance," Nagin said during an opening statement at the hearings. Maine Republican Susan Collins, chair of the Senate committee, opened the hearing with a question to Nagin about New Orleans' response to nursing home evacuations.
"I'm very hopeful that our final report will answer a lot of questions the American people have," Davis said after being presented with the GAO report. "The most obvious being: How could our government fail so badly?"
Asked by reporters whether Chertoff should have been the federal point person leading the response, GAO Comptroller General David M. Walker said: "That's up to the president of the United States."
"It could have been Secretary Chertoff, it could have been somebody on his staff," Walker said. "That's up to the president."
The report also found that other federal agencies had an "incomplete understanding of roles and responsibilities" under the National Response Plan, one area that could be solved with better training for disasters. However, it praised the Coast Guard, the Pentagon, the U.S. Postal Service and the National Finance Center for taking a "lean forward" approach to preparing for and responding to Katrina.
Though Brown was named as the top federal officer in the Gulf Coast, his authority was unclear, the report found, leading to a "disjointed" response from all federal agencies.
"In the absence of timely and decisive action and clear leadership responsibility and accountability, there were multiple chains of command," the report found.
It also noted "a myriad of approaches and processes for requesting and providing assistance, and confusion about who should be advised of requests and what resources would be provided within specific time frames."