LAS VEGAS — A union for Las Vegas casino-hotel workers is shifting its attention to negotiating contracts with smaller casino operators after reaching tentative labor agreements with two companies that employ most of the 50,000 employees threatening the first citywide strike in more than three decades.

The Culinary Union said Monday that it was now focusing on 15 properties on the Las Vegas Strip and in downtown not covered by the deals with Caesars Entertainment and MGM Resorts International. The workers without new five-year contracts could walk out of properties including the Tropicana, Treasure Island, Golden Nugget, The D and Downtown Grand at any time after authorizing a strike last month.

"The agreements with MGM and Caesars have historic language regarding immigration, technology and automation, and safety, from sexual harassment language to safety buttons," said Bethany Khan, spokeswoman for the Culinary Workers Union Local 226. "We always have one standard for our contracts, and we are going to negotiate that one standard with other properties."

BREAKINGWe are pleased to announce that a tentative agreement has been reached with @MGMResortsIntl.



The historic new 5-year contract covers approximately 24,00 workers at 10 casino resorts on the Las Vegas Strip. #OurFutureIsNow



(More details to follow) pic.twitter.com/2uJMFowRtf — The Culinary Union (@Culinary226) June 3, 2018

The largest labor organization in Nevada has declined to provide details of the tentative agreements with the two largest casino operators in Sin City because workers have not approved them. But generally, both sides agreed to wage increases and to equip housekeepers with "panic buttons" — wireless devices that workers can use to alert managers if they are in a threatening situation.

The contracts of 50,000 employees, including bartenders, housekeepers, bellmen and kitchen workers, at 34 casino-hotels expired at midnight Thursday. After talks began in February, the union reached deals with Caesars on Friday and MGM on Saturday.

Khan said the agreements include language addressing the beneficiaries of the Obama-era Deferred Action for Childhood Arrivals program and immigrants allowed to live and work in the U.S. under temporary protective status. The Trump administration has sought to end DACA, but court orders have kept the program open. It also has announced it will terminate the special protections of thousands of immigrants from several countries.

Under the tentative agreements, workers who lose their work permit and are later able to readjust their immigration status will be able to get back their casino jobs and seniority, Khan said.

"We are pleased that all economic and personal security issues have been resolved with this new contract and that employees will continue to provide guests superior service and experiences," Tom Jenkin, global president and lead negotiator for Caesars, said in a statement. "This historic agreement ensures that our union team members will continue to be a crucial part of the Las Vegas dream."

No date has been set for a possible strike, but workers have started signing up for strike pay, financial assistance and picketing shifts. If there is a strike, visitors could see workers picketing outside casino-hotels still in negotiations.

The last citywide strike was in 1984, and it cost the city and workers millions of dollars.

The union said negotiators will focus first on casino-hotels on the Strip and then on those in downtown Las Vegas.

The average worker on the Las Vegas Strip makes about $23 an hour, including benefits such as premium-free health care, a pension and a 401(k) retirement savings plan.