NEW ORLEANS (AP) - Rescue crews in New Orleans on Sunday were trying to find a worker missing in the rubble of a hotel that collapsed while under construction but work in the unstable structure must be done delicately, officials said.

Officials won't say if they have any indication whether the missing worker is alive. New Orleans Fire Chief Tim McConnell said they are going to treat their work as a rescue mission until they have evidence the missing person is dead along with two other people killed in the Saturday collapse at the Hard Rock Hotel project near the city's historic French Quarter.

"Safety is the No. 1 thing. The last thing you want to do when you are trying to rescue somebody is lose someone else," McConnell said at a Sunday news conference.

Several floors of the hotel collapsed Saturday. WWL-TV obtained a viewer's dramatic video of upper floors collapsing Saturday before one side of the building crashed to the street in a blinding cloud of dust and debris.

The bodies of the two people killed have not been recovered. Thirty people were injured. Only one remains in the hospital. New Orleans Mayor LaToya Cantrell visited the man, who had surgery for a leg injury.

"He told me it could have been worse. He wanted to make sure his co-workers were safe. He was envisioning the two who were on the floor with him," Cantrell said.

Crews Sunday morning were assembling a 220,000-pound (99,800-kilogram) crane driven into the city overnight to begin the delicate process of removing the debris, McConnell said.

"Our original estimate to get a crane was two weeks. We got it here in less than 24 hours," McConnell said.

The project's contractor, Citadel Builders LLC, was flying in engineers from Europe to help crews remove debris without risking the life of the missing person or nearby buildings and aid in the investigation, officials said.

Neither Citadel Builders nor emergency officials have commented on any potential cause of the building collapse.

The new Hard Rock Hotel was under construction at the corner of Rampart Street and Canal Street, a broad boulevard just outside the French Quarter that is lined with restaurants hotels and retailers. Canal, which carries six lanes of traffic divided by a wide median where streetcars roll, separates the Quarter from the city's main business district.

Officials warned massive disputations in the area will likely last weeks. Some debris from the building fell on the roof of the Saenger Theatre. Cantrell said the exact damage to the theater has not been determined, but productions of "Wicked" have been canceled through the end of its run next weekend. She urged patience because it could take weeks or even months to clean up the area.

"This structure is not stable. We want people to stay away from the area. How we touch it - it just matters," the mayor said.