The mayor of New Orleans ordered a mandatory evacuation of the city as Hurricane Gustav grew in ferocity, while the governor of Louisiana urged residents across the state to get out harm's way.

Early Sunday, a hurricane warning was issued for parts of the northern Gulf Coast -- including the city of New Orleans --- by the National Hurricane Center. The public advisory called for disaster preparations to be rushed to completion.

New Orleans Mayor Ray Nagin told residents of the city's West Bank, which is threatened by weak levees along at least one canal, they must evacuate starting Sunday at 8 a.m., while those in the rest of the city must leave starting at noon.

"I must tell you this is the mother of all storms...I'm not sure we've ever seen anything like it," he said at a press conference Saturday evening.

Louisiana Gov. Bobby Jindal, meanwhile, said the state on Saturday was in the process of calling 195,000 residents that live south of Interstate 10 to encourage them to heed a rash of mandatory and voluntary evacuation orders.