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House leaders continue to haggle over how to review the federal government's response to Hurricane Katrina (search) as a committee charged with overseeing the initiative prepares to begin hearings on Thursday.

Democrats have made repeated calls for an independent commission to review recovery efforts of the storm-stricken Gulf Coast. Earlier this week, President Bush (search) appointed Fran Townsend, the White House Homeland Security adviser, to investigate the response.

On Wednesday, Louisiana Gov. Kathleen Blanco joined Democratic calls, and suggested an independent panel could resemble the Sept. 11 commission.

"Only an independent, nonpartisan commission investigation that commands full support from the executive and legislative branches will accomplish what we need: a thorough, comprehensive review which is only concerned with getting to the truth," Blanco said.

Meanwhile, House Democrats restated their opposition to any panel operating within the House or Senate.

"I will not appoint any Democrats to participate in this sham," House Minority Leader Nancy Pelosi (search), D-Calif., said in a statement.

Pelosi and other Democrats blasted House Speaker Dennis Hastert (search), R-Ill., for establishing a congressional committee instead of convening an outside investigation.

"I ask the Republican leadership to join me in supporting an independent commission to determine what really went wrong in the federal response to Hurricane Katrina. The American people expect and deserve nothing less," Pelosi said.

But in a dueling press statement, Hastert issued repeated calls for Pelosi to appoint members of her party to what is supposed to be a bipartisan panel.

"I would again urge Democratic Leader Nancy Pelosi to join in this effort and not to boycott this Select Bipartisan Committee," Hastert said.

Congress has so far approved $62 billion for rescue, recovery and rebuilding in the Gulf Coast region. Congressional leaders were told earlier this week that $15 billion had already been spent.

Some lawmakers estimate the total federal dollars needed to rebuild the region to reach at least $150 billion. Federal assistance is likely to go only higher once Hurricane Rita makes landfall.

On Wednesday, Rep. Tom Davis, R-Va., who will chair the committee, sent letters to House Democrats from Gulf Coast states urging them to participate in the first hearing as witnesses.

“While it is unfortunate that the establishment of this select committee caused some partisan posturing, I believe we must now move forward together to undertake this important task,” Davis wrote in letters sent to Reps. William Jefferson and Charlie Melancon of Louisiana and Gene Taylor of Mississippi.

“I think most Americans want a rational, thoughtful, bipartisan review of what went wrong and what went right,” Davis wrote.

The House Select Bipartisan Committee to Investigate the Preparation for and Response to Hurricane Katrina is scheduled to hold its opening hearing Thursday morning. On the docket to testify are retired Brig. Gen. David L. Johnson, director of the National Oceanic and Atmospheric Administration's National Weather Service, and Dr. Max Mayfield, director of the National Weather Service's National Hurricane Center.

Next week's scheduled hearing will include testimony from former Federal Emergency Management Agency Director Michael Brown.

On the Senate side, the Homeland Security and Governmental Affairs Committee is also working to review the government's response.

The select committee was originally slated to include lawmakers from both chambers of Congress, but the Senate failed to pass legislation that would allow its members to participate. Without House Democrats on the panel, the committee is now made up of just Republicans: Reps. James Sensenbrenner of Wisconsin; Harold Rogers of Kentucky; Christopher Shays of Connecticut; Henry Bonilla of Texas; Steve Buyer of Indiana; Sue Myrick of North Carolina; Mac Thornberry and Kay Granger of Texas; Charles Pickering of Missouri; Bill Shuster of Pennsylvania and Davis.

While federal, state and local officials have been blamed for their failings to prepare for and respond quickly to the hurricane, Congress is working quickly to provide post-Katrina relief.

On Wednesday the House approved a $6.1 billion tax relief package to aid Gulf Coast residents and encourage businesses to rebuild in the region. The Senate passed the bill on a voice vote later on Wednesday and sent the bill to President Bush.