The National Labor Relations Board ruled Thursday that the Trump International Hotel In Las Vegas must recognize and bargain with the union seeking to represent its workers.

The hotel, which is co-owned by its namesake, Republican presidential nominee Donald Trump, has refused to deal with the union for a year, saying it didn't fairly win a worker election.

The ruling from the main federal labor law enforcement agency comes just days before the Nov. 8 presidential election between Trump and Democratic nominee Hillary Clinton in which Nevada remains a closely contested battleground state. The RealClearPolitics polling average gives Trump a 2-point edge there.

Trump owns 50 percent of the hotel. Unite Here, which has a strong presence in Las Vegas, petitioned the labor board to represent the hotel's workers in June 2015. An election was held in December, with the union winning 53 percent of the workers who voted. The hotel claimed fraud and filed objections less than two weeks later.

A three-member quorum of the labor board rejected the hotel's objections on Thursday and said that the union, Unite Here, is now the exclusive representative of the estimated 500 workers there.

"By failing and refusing since March 29, 2016, to recognize and bargain with the union as the exclusive collective-bargaining representative of employees in the appropriate unit, the respondent has engaged in unfair labor practices," the board said. The opinion was joined by the board's lone Republican member, Philip Miscimarra.

The conflict became an issue in the presidential campaign, with unions slamming the GOP candidate over it.

"Donald Trump is a hypocrite, whose true feelings towards working people are clear. The workers at Trump Hotel Las Vegas deserve a say in determining their wages, benefits and working conditions. Donald Trump must come to the table and negotiate with them. The labor movement will continue to stand by these hotel workers, and all working men and women, as we fight back against attacks on our rights," the AFL-CIO, the nation's largest labor federation, said in a statement Friday. Most major unions are backing Clinton in the election.

Jill A. Martin, vice president and assistant general counsel for litigation and employment at the Trump Organization, told the Washington Examiner the hotel had "no comment" on the ruling but said that the Trump Organization would appeal the board's ruling.

In a statement to the Washington Examiner earlier this year, Martin said that there had been "severe misconduct undertaken by union agents, which clearly impacted an incredibly close election."

However, in its ruling, the labor board said the hotel had not offered any new evidence regarding the election and therefore "has not raised any representation issue that is properly litigable in this unfair labor practice proceeding."