Homeland Security Secretary Michael Chertoff told reporters Sunday that "the window is closing" for people to leave the Gulf Coast in advance of Hurricane Gustav.
He described anyone who tried to brave the storm, now a Category 3 hurricane, as "exceptionally foolish."
"People should heed the instructions to evacuate and protect their own lives," he said.
Chertoff, who said he briefed President Bush Sunday morning, said "it's gonna be a very, very tough event."
Federal and state officials are working together to ensure people are leaving the area and that life and property is protected when the storm slams into communities along the coastline, Chertoff said.
"The main evacuation is going well," Chertoff said. "We are concerned because a number of the hospitals that originally planned to shelter in place have now decided they're going to actually try to evacuate their critically ill and medical needs patients. As a consequence, we've had to increase the tempo of our air flights into New Orleans in order to make sure we can accommodate the flow."
Bush will visit FEMA headquarters Sunday in Washington, according to the White House.
Chertoff, speaking to reporters at an Air Force base near the capital, said he plans to be in the region when Hurricane Gustav hits the coast.
"Hurricane Gustav is headed, I'd say at this point likely landfall somewhere between Vermilion Bay and New Orleans in Louisiana," he said. "Again, it's possible this will change, but this is where most of the prediction seems to be centered."