Finalizing the fate of Utah Theater in downtown Salt Lake City gained new urgency Tuesday with word that Mayor Jackie Biskupski had clinched an agreement to sell the Main Street property to developers with plans to raze it and build a new residential tower on the site.

Dozens of residents hoping to save the dilapidated 100-year-old performance hall wedged into a hearing room at City Hall as the city’s Redevelopment Agency (RDA) took up a proposed discount on the theater’s sales price to global real estate firm Hines and Utah-based developer LaSalle.

Artists, filmmakers, business owners, historic preservationists and residents with fond memories of the theater implored city officials to reverse course after Biskupski inked an agreement last Thursday that sets in motion the sale of the property, purchased by the city in 2010.

“Once we lose our architectural history, it is gone forever,” said resident Karel McDonough, echoing sentiments of nearly 20 theater supporters who spoke, many of them wearing “Save Utah Theater” stickers on their lapels.

The Biskupski administration has concluded the cost of restoring the theater — estimated by city officials at between $45 million and upwards of $60 million — is too high in light of other city priorities and limited budgets.

Built in 1919, the then-Pantages Theater was Salt Lake City’s showcase venue for top touring acts such as Bob Hope, Abbott and Costello and baseball legend Babe Ruth, before it was converted into a movie hall in the 1930s. Its main chamber was split into an upper and lower level in 1968, with the upper portion used to show films until it closed in 1988.

After nearly four years of negotiations with the city on ways to preserve and develop the property, adjacent property owners Hines and LaSalle are proposing to demolish Utah Theater and build a 30-story residential skyscraper, with office spaces, shops, up to 300 apartments, a mid-block walkway and a small park.

While the mayor has legal authority to dispose of city property on her own, the City Council, in its role overseeing the RDA, must approve her proposal to write down the theater’s appraised $4.07 million sales price.

Biskupski, who leaves office in January, wants to discount that price to zero, in exchange for concessions from the developers, including making about 30 of the tower’s apartments more affordable, creating the mid-block walkway and reusing iconic pieces of the theater in the new project.

Council members said Tuesday they now expect to take action on the property discount in December, effectively delaying a final decision at least for several weeks.

In an interview, a top official for Hines said the firm had spent three years and extensive resources of its own exploring ways to preserve the theater, which has sustained widespread water damage and needs seismic upgrades.

“We understand why people what to save it,” said Dusty Harris, senior managing director at Hines. “But for physical, practical and financial reason, the mayor and the RDA made the decision to move in a different direction and we’re supportive of that.”

RDA Chief Operating Officer Danny Walz warned Tuesday that borrowing up to $75 million to pay for preserving Utah Theater risked using up all of the RDA’s debt capacity for other projects in the city’s central business district, at least until 2040.

“I cannot recommend that,” Walz said.

But supporters of the theater said the city’s preservation costs were inflated, especially when compared to restorations of near-identical Pantages Theaters from the era in Tacoma and Minneapolis.

They also repeated claims the city has not adequately included the public in its decisions along the way, ignoring what they say is deep-seated community support for the theater.

Pete Ashdown, organizer of an online campaign to preserve the building and its unique neoclassical interior, noted his petition had drawn 3,600 signatures in three weeks. He said Biskupski had “doomed” the theater without adequate public input and called for a halt to the sale while other options are explored.

“Please do not be complicit in her action,” Ashdown said. “You are the counterbalance to the mayor.”

The public input Tuesday brought mixed reactions from council members, although Erin Mendenhall, recently elected to replace Biskupski, and Chris Wharton were not present for the discussion.

“I’m struggling with this one,” said Councilman Andrew Johnston, who, with Councilwoman Ana Valdemoros, called on the mayor to pause the sale.

“I want to exhaust every single option we have,” added Valdemoros, whose district includes the theater site.

Councilman James Rogers countered that he was comfortable moving forward with the sale and the developers’ plans.

“To me, it doesn’t pencil out,” Rogers said of preserving Utah Theater. “As a board member, I’ve heard enough from two administrations and nothing is happening.”

With a vote pending in December, Johnston urged residents, potential donors and others with concrete proposals on how to save the building to come forward.

“It has to happen now,” he said.