(Reuters) - The general counsel of a U.S. labor agency has accused Chipotle Mexican Grill Inc of violating U.S. labor law by allegedly firing an employee in New York in retaliation for complaining about workplace problems and trying to organize with a union.

FILE PHOTO: The logo of Chipotle Mexican Grill is seen at the Chipotle Next Kitchen in Manhattan, New York, U.S., June 28, 2018. REUTERS/Shannon Stapleton

The office of the general counsel of the National Labor Relations Board (NLRB) filed the complaint on Dec. 12. The union involved, 32BJ, which is trying to organize workers at the Mexican fast-casual restaurant chain, received a copy of the complaint on Thursday.

Because Chipotle’s restaurants are all owned by the corporation as a single employer, it is an easier target for union organizers than fast-food giant McDonald’s Corp, most of whose locations are owned and operated by franchisees.

Chipotle spokespeople did not provide an immediate response to requests for comment.

The NLRB’s general counsel, Peter Robb, alleged in the complaint that a manager at a restaurant in Manhattan in May threatened to fire employees if they engaged in union activities - even implying they might face physical violence - and promised promotions to other workers who provided information about the organizing.

The complaint, which was filed with the NLRB, also alleges similar manager intimidation at another Manhattan store. One employee who complained about scheduling and other problems was fired.

The complaint asks that Chipotle reimburse the fired employee for expenses incurred from work searches and for tax relief from any lump sum back pay awards. The complaint seeks no other remedy.

The NLRB’s general counsel operates independently from the Board and is responsible for investigating and prosecuting unfair labor practices. Robb, who has been general counsel since November 2017, was appointed by President Donald Trump.

The parent of 32BJ, the Service Employees International Union, is involved in the Fight for $15 and a Union, which has long sought to organize workers at McDonald’s.

That effort suffered a setback of sorts last week when the full NLRB board approved McDonald’s Corp’s proposed settlement allowing the fast-food company to avoid a ruling on whether it is a “joint employer” of franchise workers and could be made to bargain with unions.

While Fight for $15 and a Union said it would appeal, the decision suggests it may be a long road for organizers if they are not able to target the parent corporation and must instead bargain with thousands of individual U.S. owners.

Chipotle must respond to the complaint by Dec. 26 and a hearing is set for March 2 in New York.