Lt. Gen. Steven Blum, chief of the National Guard Bureau, said that "arguably" a day or so of response time was lost due to the absence of the Mississippi National Guard's 155th Brigade Combat Team and Louisiana's 256th Infantry Brigade, each with thousands of troops in Iraq.

"Had that brigade been at home and not in Iraq, their expertise and capabilities could have been brought to bear," said Blum.

Blum said that to replace those units' command and control equipment, he dispatched personnel from Guard division headquarters from Kansas and Minnesota shortly after the storm struck.

Rep. Gene Taylor, D-Miss., whose waterfront home here was washed away in the storm, told reporters that the absence of the deployed Mississippi Guard units made it harder for local officials to coordinate their initial response.

"What you lost was a lot of local knowledge," Taylor said, as well as equipment that could have been used in recovery operations.

"The best equipment went with them, for obvious reasons," especially communications equipment, he added.

Defense Secretary Donald H. Rumsfeld said this week that the Pentagon has the ability to cope with both Katrina and the Iraq war: "We can and will do both."

Asked on Tuesday about critics who said the commitment of large numbers of troops to the Iraq conflict hindered the military's response to Hurricane Katrina, Rumsfeld said, "Anyone who's saying that doesn't understand the situation."