Boeing and unions arrived at a stalemate in the third week of a standoff over pay, with Boeing withdrawing a 30% pay offer for striking workers.

The Guardian reports that the U.S. planemaker said it had removed its offer that would result in a pay increase by almost a third over three years for 33,000 U.S. staff, with no further negotiations with the International Association of Machinists and Aerospace Workers (IAM) planned.

Boeing and the union held their latest round of negotiations with federal mediators on October 7 and 8, but talks collapsed with both parties locked in an acrimonious stalemate showing no signs of a rapid solution, Reuters reported.

“Unfortunately, the union did not seriously consider our proposals,” the Boeing Commercial Airplanes chief executive, Stephanie Pope, said in a note to employees, calling the union’s demands “non-negotiable”. She said: “Further negotiations do not make sense at this point and our offer has been withdrawn.”

The IAM, which is demanding a 40% increase for staff, has accused Boeing of being “hell-bent on standing on the non-negotiated offer” proposed in September.