Obama toured St. John the Baptist Parish late Monday, about 50 kilometers outside of New Orleans, and met with residents, some of whom were forced to flee floodwaters by rushing to their rooftops to await rescue.

"One thing you know about folks in Louisiana, they are resilient," said President Obama. "People in Mississippi, they are resilient.  They know what tough times are like but they know that they can bounce back."

Obama also praised the Republican governor of Louisiana, Bobby Jindal, and all the local and federal officials who have been helping with recovery efforts.

"When disasters like this happen, we set aside whatever petty disagreements we may have," said Obama. "Nobody's a Democrat or a Republican.  We're all just Americans looking out for one another."

Earlier in the day, Obama rallied blue collar workers in the nation's heartland, giving a Labor Day holiday address to unionized auto workers in Toledo, Ohio.  He cited the U.S. auto industry's comeback as a success for his administration.

"I stood with American workers. I stood with American manufacturing," he said. "I believed in you. I bet on you. I'll make that bet any day of the week. And because of that bet, three years later, that bet is paying off for America."

In contrast, Republican presidential challenger Mitt Romney said Labor Day was "a chance to celebrate the strong American work ethic." But he said that for many jobless Americans it is "another day of worrying" when their next paycheck will come.

The Democratic National Convention - where Obama will be formally nominated for a second term - opens Tuesday in Charlotte, North Carolina.

The U.S. has the world's largest economy, but it has struggled to regain its economic footing. The country's jobless rate remains above an unusually high 8 percent and the sluggish economy has imperiled Obama's re-election chances. Surveys show him in a virtual tie with Romney.