NEW ORLEANS (AP) — On the same day that residents marked the three-year anniversary of Hurricane Katrina’s wrath, another storm strengthened into a hurricane miles away and threatened to hit the Gulf Coast once again.

Forecasters at the National Hurricane Center said Friday afternoon that Gustav had grown into a Category 1 storm, and remained on track to strike anywhere from the Florida Panhandle to eastern Texas sometime next week.

The news came only hours after New Orleans lay to rest the last seven unclaimed Katrina victims. A horse-drawn carriage brought the bodies for entombment at a memorial site, and the mayor helped guide a gleaming casket into a mausoleum.

The ceremonies were tinged with an awareness of how far the city has come since Katrina, but also a trepidation about the possibility of another storm.

‘‘We look ahead to a better day, as we also prepare ourselves for another threat,’’ Mayor Ray Nagin said as he helped guide a gleaming coffin into a mausoleum.

Most other remembrances were called off as officials scurried to plan for Hurricane Gustav. National Guard members were reporting to armories, while some nursing homes and hospitals planned to start moving patients further inland and the state began moving 9,000 inmates from coastal lockups.

‘‘I think God is reminding us that on the eve of Katrina, God can bring nature back,’’ said Russell Honore, the retired Army General who headed up rescue efforts three years ago.

Gustav has been blamed for 71 deaths on its path through Haiti, the Dominican Republic and Jamaica. Along the Gulf Coast, officials were preparing for the possibility of major evacuations should the storm stay on track. Mississippi Gov. Haley Barbour had already called for the evacuation of Katrina-scarred residents still living in trailers and other temporary housing along the state’s 70-mile coastline. The mayor of Grand Isle, La., also called for voluntary evacuations.

President Bush declared an emergency in Louisiana, a move that allows the federal government to coordinate disaster relief and provide assistance in storm-affected areas. A federal declaration before a storm is rare, but Bush took a similar action for Louisiana, Mississippi, Alabama and Florida before Katrina’s landfall.

An evacuation order for New Orleans was likely, Nagin said, but not before Saturday. Gustav confounded emergency preparedness officials as its forecast track shifted slightly through the day, confronting them with the possibility of ordering evacuations not only in the potentially vulnerable New Orleans area but across more than 200 miles of coastline.

Harvey Johnson, deputy administrator of the Federal Emergency Management Agency, said during a conference call that he expects a ‘‘huge number’’ of Gulf Coast residents will be told to leave the region this weekend.

New Orleans said it is prepared to move 30,000 residents in an evacuation; estimates put the city’s current population between 310,000 to 340,000 people. There were about 454,000 here before Katrina hit. Unlike Katrina, there will be no massive shelter at the Superdome, in fact, no shelter at all was planned for the city. It was unclear what would happen to those left behind. The first 150 of 700 buses to move residents inland arrived at a staging area near New Orleans on Thursday.

At 5 p.m. EDT, Gustav’s center was about 100 miles east of Grand Cayman. The storm was predicted to pass on or near the Cayman Islands later Friday, then over western Cuba on Saturday before heading into the Gulf.

The Hurricane Center also issued a tropical storm watch for the lower Florida Keys from west of the Seven Mile Bridge westward to Dry Tortugas National Park. While Gustav’s center was expected to pass west of Florida, tropical storm force winds extended outward up to 160 miles from the storm’s center.

Forecasters said for the first time that there’s a better than ever chance that New Orleans will feel at least tropical storm-force winds. There was much less confidence in whether the city would get hit by hurricane-force winds.

Melissa Clark, who lives in neighboring Jefferson Parish, said she’s leaving Friday with her family to stay with friends in Clinton, Miss. — evacuation order or not. Her husband, who works in maintenance at a nearby hospital, will stay behind.

‘‘I’m not taking any chances this time,’’ the 35-year-old mother of three teenagers said as she waited fifth in line at a Wal-Mart gas station Thursday.