Outside the Plaza Hotel yesterday, the rally was called a prayer vigil, replete with the moral authority of a rabbi, an imam, and Reverend Jesse Jackson, all calling for the preservation of union jobs.

Inside the hotel’s musty Oak Room, a spokesman for the Plaza’s owner, Elad Properties, stood before reporters and made an economic appeal: a $350 million renovation, $100 million in new tax revenue for the city, with a potential $415.6 million in goods and services purchased by the hotel’s wealthy residents. Elad is seeking to turn the 805-room hotel into nearly 1 million square feet of mixed-use space, including condominiums and retail space as well as a much smaller number of hotel rooms.

And in the middle of the fight over the future of the Plaza stands a businessman-turned-politician, Mayor Bloomberg.

Last month, representatives of the mayor met with both sides at Gracie Mansion, and there have been several discussions since.

“The city itself is a disinterested mediator between both sides in the dispute, and we haven’t taken a particular position on any of the proposals,” a spokesman for the mayor, Jordan Barowitz, said. “Our goal is to help mediate the dispute.”

But not getting pulled into the fray, as each side makes its public appeals, has been difficult.

Yesterday, the president of the union representing the hotel workers, the New York Hotel and Motel Trades Council, told about 500 supporters that the mayor recently joined his political rival Gifford Miller in supporting the union’s efforts to save the hotel and preserve union jobs. The spokesman for Elad, Bruce Teitelbaum, contested that claim and praised Mr. Bloomberg for saying he would remain impartial.

“The mayor has been extremely supportive,” Mr. Teitelbaum said. “My sense is that this administration is very supportive of business and very supportive of expanding and creating economic opportunity.”

Elad Properties bought the hotel for $750 million and plans to lay off all 914 union and 147 nonunion employees by April 30 to begin renovations. When it reopens in late 2006, the Plaza expects to hire 658 employees, with 150 of them unionized hotel workers, Mr. Teitelbaum said.

Though union leaders ballyhooed a community board decision last week rejecting the company’s request for special permits for the renovations, the vote carries no legal authority. “Ours is an advisory ruling,” the district manager of Community Board 5, Gary Parker, said.

The next step for Elad is securing the permits from the city’s Landmarks Preservation Commission, but complying with requirements for a designated historic landmark does not mean the company cannot turn the Plaza into a mixed-use site, landmarks experts said.

That leaves “the court of public opinion,” where the union hopes to wage and win its battle to keep the Plaza a large hotel, a union spokesman, John Turchiano, said.

Despite Elad’s assurances that their plans for the Plaza would preserve its status as a beloved public icon, supporters of the union voiced frustrations. A film producer, Rose Ganguzza, who said she helped bring hundreds of movie shoots to the hotel, summed up what she called a lack of understanding by the hotel’s current and recent owners.

“All they were concerned about was bricks and mortar, and not the emotional real estate they owned,” Ms. Ganguzza, 56, said.

A proposal made by Elad Properties to open a new hotel elsewhere in the city, as a joint venture with the union intended to save jobs lost at the Plaza, has been dismissed by the union, which called the deal ridiculous and a conflict of interest. That left the two sides at an impasse.