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As Hurricane Isaac neared the Gulf Coast, President Barack Obama said Tuesday that Americans will help each other recover, "no matter what this storm brings."

"When disaster strikes, we're not Democrats or Republicans first, we are Americans first," Obama said at a campaign rally at Iowa State University. "We're one family. We help our neighbors in need."

Preparations for the storm have been under way for days, Obama said, vowing that the nation will be prepared for likely flooding and other damage from the hurricane, which was expected to hit Louisiana, possibly the New Orleans area, Tuesday night or early Wednesday.

Obama warned Gulf Coast residents to listen to local authorities and follow their directions.

"Now is not the time to tempt fate. Now is not the time to dismiss official warnings. You need to take this seriously," Obama said.

Even before the storm hit, Obama declared an emergency exists in Mississippi on Tuesday and ordered federal aid to supplement state and local storm response efforts there. The president declared a state of emergency in Louisiana late Monday, more than 24 hours before the storm was expected to hit the Gulf Coast. The declaration makes federal support available to save lives, protect public health and safety and preserve property in coastal areas.

The White House is aiming to balance leadership on the storm with the president's campaign plans. Obama made brief remarks about the storm from the White House Tuesday morning before departing on a two-day campaign trip to Iowa, Colorado and Virginia.

Obama aides said that while there were no current plans to change the president's travel itinerary, the White House was monitoring the storm and would adjust his schedule if necessary.

Republicans canceled the first day of their convention in Tampa when the storm appeared to be headed for landfall in Florida. But the party is resuming convention activities Tuesday.

Obama campaign spokeswoman Jen Psaki told reporters Tuesday that while Obama would address storm developments during his travels, the focus of his trip would be to make his case for re-election to young people.

"It's important for him to be out there less than 70 days before the election making the case for why he's a better choice for the American people," she said.

The tropical storm was upgraded by forecasters to hurricane status at midday and it now is categorized as a Category 1 Hurricane as it veers toward New Orleans.

Louisiana Gov. Bobby Jindal, a Republican, said the emergency declaration signed by Obama fell short of the help he was requesting. Jindal wants the federal government to reimburse state and local government agencies for the storm preparation efforts.

That reimbursement declaration can be done after the hurricane passes. But Jindal said Tuesday, "We learned from past experiences, you can't just wait. You've got to push the federal bureaucracy."

Asked about the criticism, White House press secretary Jay Carney said there would be time to explore whether additional disaster declarations are needed.

Obama has asked the Federal Emergency Management Agency to coordinate disaster relief efforts with state and local officials along the Gulf Coast. FEMA has placed incident-response teams at emergency operations centers in Gulf states and has moved two support teams near areas where the storm could hit. More teams also are ready to be deployed if necessary, the White House said.

FEMA has distribution centers in Atlanta and Dallas-Fort Worth area, and in coordination with the Defense Department, has pre-positioned supplies in Jacksonville, Fla. and Montgomery, Ala., closer to areas where the storm could hit.

Forecasters predict Isaac will intensify into a Category 2 hurricane with winds of about 100 mph by early Wednesday, with a projected path directly toward New Orleans. Isaac could become the first hurricane to hit the Gulf Coast since 2008.

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Daly reported from Washington. Associated Press writer Melinda Deslatte in Baton Rouge, La., contributed to this story

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