NEW ORLEANS (AP) — New Orleans residents scrambled Monday to stockpile food, fuel and other supplies as they prepared to ride out a storm that was due to arrive on the seventh anniversary of Hurricane Katrina.

New Orleans Mayor Mitch Landrieu said the city is ready to face Isaac. He urged about 900 residents who live outside levee protection in eastern New Orleans to evacuate, but he ruled out a mandatory evacuation of the city inside the levee system.

“There is a point beyond which a mandatory evacuation would not be possible. I believe that we’re at that point,” Landrieu said at an afternoon news conference.

Earlier Monday, the mayor said a mandatory evacuation would come if Isaac attained Category 3 strength on the 5-point Saffir-Simpson scale. Instead, he urged residents to hunker down and make due with supplies on hand.

“Notwithstanding the fact that we are not expecting a Katrina-like event — that is, breaking the levees and that kind of flooding in the city — a Category 1 and a Category 2 storm can bring significant damage,” Landrieu said.

As Isaac moved steadily toward Louisiana, residents geared up for what has become an almost familiar Labor Day week event.

On Sunday, Gov. Bobby Jindal declared a state of emergency, and officials in some coastal parishes either ordered evacuations or strongly suggested people leave low-lying areas, particularly among coastal parishes.

“Today is the day to move,” Jindal said at a news conference Monday at City Hall in New Orleans.

More than 4,100 Louisiana National guardsmen have been deployed throughout the state to respond to the storm and its aftermath, Jindal said.

Grocery and home improvement stores as well as fuel stations reported brisk business. Some gas stations were running out of supplies.

Harvey Burns, 55, was filling up his vehicle so his son, a Marine, could drive to Galveston, Texas, later Monday. It wasn’t an evacuation, just a pre-existing plan to head to school. Burns planned to stay in New Orleans and ride out the storm at home.

“It’s not a big deal right now. It’s a tropical storm. It’s kind of hyped up because of the timing of it,” he said, alluding to the storm’s expected landfall by Wednesday, Katrina’s seventh anniversary.

Cheryl Chen, 25, was gassing up her car to drive to the airport to catch a flight Monday night to Virginia to be with her boyfriend. She planned to leave Tuesday, but her flight was canceled. She’s been working at a New Orleans hotel for the past six months or so and has never experienced a hurricane before.

“That’s why I’m so freaked out,” she said.

John Corll, 59, a carpenter, rode out Hurricane Katrina seven years ago and was preparing for a milder storm.

“I gassed up — truck and generator,” Corll said as he walked out of a New Orleans coffee shop Monday morning.

He expressed confidence that the area’s levee system — rebuilt with billions of federal dollars after Katrina — will withstand Isaac.

And he thinks emergency management officials have a better handle on the situation than when Katrina struck in August 2005.

“I think the state and local governments are much better prepared for the storm surge and emergencies,” he said.

An estimated 80 percent of New Orleans was flooded during Katrina when it struck on Aug. 29, 2005. Damage and death was extensive across southern sections of Louisiana, Mississippi and Alabama and rebuilding costs soared into the many billions of dollars.

Adding to the Labor Day week mystique, in 2011, Tropical Storm Lee struck and Hurricane Gustav hit over the Labor Day holiday in 2008.

While Isaac was not expected to approach Katrina’s strength — or Gustav’s — forecasters said it should bring high winds, heavy rain and a storm surge of up to 12 feet into coastal Louisiana and Mississippi. On its projected path, it would drive inland, possibly bringing heavy rain to drought-parched heartland states.

The Coast Guard said barges were being moved inland on the Mississippi River. Ship traffic was halted at the river’s mouth on Sunday night.

Officials at Louis Armstrong New Orleans International Airport said flights were continuing, but carriers such as Southwest, United and American were planning to cancel flights on Tuesday.

Some school systems and universities in southeast Louisiana were closed through Wednesday or were considering closures.

Jefferson Parish President John Young said the New Orleans suburb is preparing for Isaac but expects that pumping and levee improvements made since Katrina will be adequate to deal with Isaac.

In coastal Lafourche and Terrebonne parishes, parish officials were distributing sandbags to residents to shore up their properties.

State transportation officials suspended tolls on the Louisiana Highway 1 bridge in Lafourche Parish to help with coastal evacuation. Tolls also were suspended on the Crescent City Connection, the bridge that links downtown New Orleans with communities on the west bank of the Mississippi River.