The NFL Referees Association has filed an unfair labor practice charge against the league with the National Labor Relations Board.

The referees association announced Thursday that it had filed the charge Tuesday. It accuses the league of providing inaccurate information about the NFL’s proposals in general mailings to members of the referees association.

“It is clear the league never intended to work toward a fair agreement, even through mediation,” Mike Arnold, lead negotiator for the referees, said in a written statement. It is not clear when the NLRB might act on the referees’ accusation.

The league denied wrongdoing, issuing a written statement that said: “There is no merit to these claims. It is common for employers during collective bargaining to provide factual information to employees that has already been communicated to the union. That is all that was done here.”

The league has locked out the referees, whose labor deal expired at the end of May, and has taken steps to begin the upcoming season with replacement officials if a new pact is not reached before then. The two sides agreed to the involvement of federal mediators but have remained unable to reach an agreement.