NEW YORK (AP) -- Two people familiar with the talks say that the NFL and the locked out officials' union met on Sunday.
It was uncertain whether progress was made in an attempt to reach a new collective bargaining agreement, or when further negotiations would take place.
The two people spoke to The Associated Press on the condition of anonymity because the talks are not being made public.
The NFL locked out the officials in June after their contract expired. The league has been using replacement officials, and through three weeks of the regular season there has been much criticism over the way some games are being handled.
Earlier Sunday, the NFL players' union sent an open letter to team owners calling for an end to the lockout.