Bush, speaking to reporters in Washington Sunday, said he had been briefed by U.S. Homeland Security Secretary Michael Chertoff on hurricane recovery efforts.
"This is a tough storm, and it's one that is going to require time for people to recover," Bush said.
"First priority is search and rescue. And I want to thank the people at the federal and state levels for working so hard to rescue our fellow citizens from harm's way."
Texas Gov. Rick Perry is conducting the state's largest-ever search-and-rescue mission, with more than 1,500 people looking for survivors.
Bush also emphasized that restoring electricity is shaping up as an important task. Officials have estimated 5 million people living along the Gulf Coast in Texas and Louisiana were without power Sunday.
"Interestingly enough, some electricity is already being restored to Houston, I'm told," said Bush, who had been briefed by U.S. Energy Secretary Samuel Bodman. "And I do want to thank the utility companies for working hard to get electricity up."