(Reuters) – A union representing flight attendants for American Airlines Group Inc on Friday asked workers to prepare for strike action after contract negotiations with the carrier failed to produce an agreement.

“We remain apart on the key economics of the deal plus the company’s completely unacceptable demand for scheduling concessions,” the Association of Professional Flight Attendants (APFA) said in a statement.

APFA said it believes that the National Mediation Board (NMB) which is overseeing the negotiations will bring the parties together for a “last ditch” effort in the next two weeks.

American Airlines and the NMB did not immediately respond to request for comment outside regular business hours.

Lawmakers in the U.S. have urged the NMB to take steps to help about 80,000 flight attendants reach contract deals.

Flight attendants at United Airlines, Alaska Air group, American Airlines and Frontier are among employees at more than a dozen airlines still working to reach new contract deals.

(Reporting by Utkarsh Shetti in Bengaluru; Editing by Shri Navaratnam)