Irish retailer Primark, which opened its first U.S. store in Boston a little over two months ago, is already embroiled in a full-scale labor dispute in the country, the Boston Globe reports.

Union officials claim the low-cost fashion chain has fired at least 50 people at the Downtown Crossing location for backing organizing efforts. The union has filed charges with the National Labor Relations Board.

The company, which has many unionized employees in Europe, denies the charge, saying workers have been let go due to poor performance, not union activity.

“Primark has not discharged any employee for their support of the union,” the company said in a statement. “While some terminations have occurred, most were for those who had poor attendance, stopped showing up for work, and/or engaged in employee misconduct.”

United Food and Commercial Workers Union Local 1145 began organizing Primark employees and holding demonstrations before the store opened in September. It said that more than 260 of the store’s 500 workers have signed cards indicating interest in joining a union. For the union to formally organize, the majority of employees must show that they are in favor, but that majority is now in jeopardy after 50 employees have been let go.

One Primark employee, Sonya Joseph, 40, said that after she signed up with the union, her schedule was changed to times she couldn’t work.

Erica Morrison, 24, said she missed several days of work for health reasons, but it was only after she expressed interest in the union that she was fired.

“After I signed the [union] card, that was when I started to get harassed,” she said.

Local 1145 has filed a charge with the labor board alleging that Morrison was fired for engaging in union activity, the Boston Globe reports.

According to union officials, Primark did not initially interfere when organizers started signing up employees in front of the store. However, they claim that as more workers became interested in unionizing, the company started discouraging union involvement, asking people who had signed cards to raise their hands at meetings.

Primark said there is “no basis for this allegation.”

The company claims the union has intimidated workers to get them to join, which the union has denied.

In a statement, Primark, which has noted that many of its 62,000 employees around the world are unionized, said it respects workers’ right to join a union.

“Primark has a long history of working cooperatively with unions throughout the world and certainly has no bias against unions,” the company said in a statement. “Primark will not influence the decision of employees as to whether or not to have a union.”