Updated

Bernie Sanders campaign staffers reportedly donned union pins to try to get close to culinary workers at several major hotel restaurants in Las Vegas -- drawing objections from union bosses.

Journalist Jon Ralston broke the story on his website Thursday, and it was later reported in Politico and The Hill. According to Ralston, the two Nevada staffers wore “Local 226” pins to gain entry into employee dining halls at Planet Hollywood, The Mirage, The Rio and Paris.

"We are disappointed and offended. It's completely inappropriate for any campaign to attempt to mislead Culinary Union members, especially at their place of work," Geoconda Arguello-Kline, union treasurer, said in a statement to Politico.

Not only did the implied union membership give the staffers -- unnamed in the report -- access to hundreds of union voters ahead of the Feb. 20 Democratic caucuses, but the move could have wrongly suggested the union was taking sides in the primary race.

It is not.

“We strongly condemn anyone falsifying their affiliation with the Culinary Union in order to gain access to properties and we will cooperate with casinos and hotels so that this matter is fully resolved,” Arguello-Kline said.

The union has 60,000 members in the state, including tens of thousands of employees who work on the famed Las Vegas strip. This can translate into a massive voter mobilization machine, particularly for Democrats, during presidential elections.

While the union backed then-Sen. Barack Obama over Hillary Clinton in the 2008 caucuses, it is expected to hold its endorsement for 2016 until the contests are over, according to Politico. In the meantime, the union has plans to register 10,000 new voters among its membership in the next six months.

When contacted by FoxNews.com, the Sanders' campaign said it confirmed staff were in the dining halls but did not address the pins.

"It appears that some of our organizers were reaching
out to Local 226 members in their dining spaces.  We have reminded our staff that that is not appropriate and that they should not do it again," said campaign manager Jeff Weaver.

"In addition, I have spoken with the political director of
the Culinary Union to express the campaign’s regret at this having
occurred and our support of the union’s fight for workers’ rights," he added.

"The political director was extremely gracious and we are glad to have this resolved."