WASHINGTON – Federal Emergency Management Agency director Mike Brown resigned Monday, three days after losing his onsite command of the Hurricane Katrina relief effort. The White House picked a top FEMA official with three decades of firefighting experience as his replacement.

R. David Paulison, head of FEMA's emergency preparedness force, will lead the beleaguered agency, according to three administration sources who spoke on condition of anonymity because the announcement had not yet been made.

Paulison is a career firefighter from Miami who was among emergency workers responding to Hurricane Andrew in 1992 and the crash of ValuJet Flight 592 in the Florida Everglades in 1996, according to a biography posted on FEMA's Web site. He also has led the U.S. Fire Administration since December 2001, according to the site.

As chief of the Miami-Dade Fire Rescue Department, Paulison led 1,900 personnel under a $200 million operating budget. He was also in charge of Dade County's emergency management office, according to his biography.

Paulison will lead an agency that has been under fire for its response to the Katrina disaster. Local officials and members of Congress have cited confusion and a lagging response to the Gulf Coast devastation.

Brown had taken much of the heat and was relieved of his onsite command on Friday. In an interview Monday with The Associated Press, Brown said he resigned "in the best interest of the agency and best interest of the president." He said he feared he had become a distraction.

"The focus has got to be on FEMA, what the people are trying to do down there," Brown said.

His decision was not a surprise. Brown was abruptly recalled to Washington on Friday, a clear vote of no confidence from his superiors at the White House and the Homeland Security Department. He also was accused of padding his resume, which Brown has denied.

The president ducked questions about Brown's resignation. "Maybe you know something I don't know. I've been working," the president said to reporters on an inspection tour of damage in Gulfport, Miss. Bush said he planned to talk with Brown's boss, Homeland Security Secretary Michael Chertoff, from Air Force One on the flight back to Washington.

"There will be plenty of time to figure out what went right and what went wrong," Bush said.

Polls show most Americans believe Bush could have done more to help Katrina's victims, though they also blame leaders of Louisiana and New Orleans. Bush's overall job approval rating is at the lowest point of his presidency.

House Democratic Leader Nancy Pelosi called Brown's departure long overdue.

"His resignation is the right thing for the country and for the people of the Gulf Coast states," Pelosi said in a statement.

Brown, who said he last talked to Bush five or six days ago, said the resignation was his idea. He spoke Saturday to White House chief of staff Andrew Card, who did not request his departure, according to Brown.

"I'm turning in my resignation today," Brown said. "I think it's in the best interest of the agency and the best interest of the president to do that and get the media focused on the good things that are going on, instead of me."

Shortly after Brown was recalled to Washington last week, officials close to the FEMA director said he would probably resign. They said that even before Katrina, Brown had been planning on leaving the administration late this fall to go into the private sector.

Associated Press writers Jennifer Loven in Mississippi and Ron Fournier, Nedra Pickler and Randolph E. Schmid in Washington contributed to this report.