A rally Monday to save the Plaza will double as a prayer vigil, as it has become increasingly likely that only divine intervention can save 900 jobs at the historic Fifth Avenue hotel.

Reverend Jesse Jackson, who will be the guest speaker at the noon rally outside the hotel, is to be joined by other religious leaders for what the union hopes will lead to a peaceful resolution to its fiery battle with Elad Properties, which recently bought the world-famous hotel and plans to convert most of it into condominium apartments and retail space.

Union workers, represented by the New York Hotel Trades Council, have been protesting the impending loss of their jobs when the Plaza is shuttered next month for its partial conversion to condos. Elad expects to reopen the building in 2006 with only a fraction of its rooms still used as hotel rooms.

A spokesman for the union, John Turchiano, said he expects the rally to draw about 1,000 people.

Mr. Turchiano said the rally was scheduled because union members were incensed after receiving Wednesday what he described as a “rather nasty and abusive letter from the owner.”

The letter, which was distributed to all Plaza employees, states: “The Plaza will close its doors on schedule, effective April 30. We have told that to you, your union, and our guests. Nothing that the union’s destructive political and public relations campaign against us can do will change this reality. We only think it’s fair to let you know that.”

Elad said in the letter that efforts by the union to interfere further with the plans for conversion are futile and are hurting union employees.

“The Plaza is working to improve the property and is doing everything it can to lessen the burden on the union workers who may lose their jobs, including making an offer to double severance pay, which the union has rejected,” an Elad spokesman told The New York Sun yesterday.

The letter to workers says: “If anybody tries to convince you that these efforts stand the slightest chance of keeping the Plaza the way it currently is – or of increasing the number of hotel jobs after the renovation is complete – they are wrong and you shouldn’t be deceived.”

Speaking of the letter, Mr. Turchiano said: “We’re hoping a peaceful prayer vigil might keep this dispute respectful, or certainly above the level Elad stooped to.”

In response to the union’s rally plans, an Elad spokesman, James Grossman, said the company is looking forward to hearing what Rev. Jackson has to say.

“The Plaza believes anything Reverend Jackson can offer to achieve a positive resolution to this is good for everybody,” Mr. Grossman said.