Republican lawmakers raised concerns Wednesday about President Bush's push to expand the Pentagon's response role during disasters like Hurricane Katrina, fearing the military could be stretched too thin.

"To an American public understandably upset by the slow response to Hurricane Katrina and frightened by a possible avian flu outbreak, the president's suggestion merits discussion," Rep. Dave G. Reichert told a House panel.

However, "if the military assumes primary responsibility for both national defense and emergency response then its dual missions may drain valuable resources and personnel," said Reichert, R-Wash.

Bush proposed putting the Pentagon in charge of search-and-rescue efforts for catastrophic natural disasters in the aftermath of the government's sluggish response to Katrina, which devastated the Gulf Coast on Aug. 29. That mission is currently coordinated by the Homeland Security Department, which oversees the Federal Emergency Management Agency.

Lawmakers also questioned whether expanding the military's mission would take away too much authority from state and local officials. They also noted laws that prohibit active duty troops from undertaking police duties or other domestic law enforcement activities.

"These are important precedents here that we're trying to get at," said Rep. John Kline, R-Minn. "And I think there's just confusion."

Assistant Secretary of Defense Paul McHale said the Pentagon intends to play a support role to Homeland Security response coordination efforts. Additionally, National Guard chief, Lt. Gen. H. Steven Blum, said "there is always one person in charge" in states where catastrophes hit -- elected governors.

McHale acknowledged what he called a "real challenge" for officials to decide how quickly the Pentagon should respond to devastating disasters, and whether it should lead those missions.

Rep. Bennie G. Thompson of Mississippi, the top Democrat on the panel, said Homeland Security should remain in charge of disaster response mission, but that it needs to do a better job of coordinating those efforts.

"The real issue is whether or not the Department of Homeland Security is doing its job," Thompson said.