LAS VEGAS – Sen. Bernie Sanders took to Twitter on Tuesday and called for owners of the Palms casino-resort west of the Strip to negotiate with workers seeking a union contract.

The 77-year-old self-described Democratic Socialist running for president characterized Palms leadership as "billionaire, Trump-supporting owners."

The Palms is owned by Station Casinos and brothers Frank Fertitta III and Lorenzo Fertitta – cousins of Tilman Fertitta, who bought Atlantic City’s Golden Nugget casino from President Donald Trump’s former company, and Landry’s Inc., one of the nation’s largest restaurant companies. All three Fertittas have been ranked on the Forbes 400 List of Richest Americans.

In April, Palms workers voted to unionize. The Culinary Union represents about 900 porters, food servers, bartenders and other workers there.

The company challenged the election’s result but the National Labor Relations Board determined the company has been “failing and refusing to bargain collectively and in good faith” with the Culinary Union.

“With respect to the Palms, although the union would clearly prefer that we not exercise our legal right to challenge the National Labor Review Board’s decision in the United States federal courts – we have every right to do so and our challenge is both legal and appropriate,” said Michael Britt, a senior vice president for Station Casinos’ parent company, Red Rock Resorts, in a statement to the USA TODAY Network.

The Palms is one of six Station Casinos properties in Las Vegas. In June, more than 1,000 members of a casino workers’ union and other hospitality union members picketed.

They wore their signature red shirts and chanted while carrying signs that said, “No contract. No peace.”

Culinary Union secretary-treasurer Geoconda Argüello-Kline says Station Casinos is disrespecting workers by refusing to come to the bargaining table and the union won’t stop until they negotiate.

Contributing: The Associated Press.