The union representing thousands of striking Boeing workers says a survey of its members shows they are “not interested” in the aviation giant's latest pay offer.
“Many comments stated that the proposal was inadequate,” the International Association of Machinists and Aerospace Workers (IAM) said in a post on X.
The move comes after Boeing earlier this week made a new proposal to striking workers, offering a 30% pay hike over four years.
BBC News has sought a statement from Boeing in response to the IAM's announcement.
“The results of yesterday's survey were very clear, almost the same as the first proposal: members have no interest in the company's latest proposal, which was sent out through the media,” IAM Post said,
On Monday Boeing presented its “best and final” pay offer, which included the reinstatement of performance bonuses, improved retirement benefits and a one-off $6,000 (£4,470) bonus for signing the new pay deal.
The company said the offer is subject to approval by union members by midnight Pacific time on Friday, September 27 (7:00 GMT on Saturday, September 28).
However, IAM said Boeing had sent the new proposal directly to union members and the media without informing union representatives.
She also said the company’s timelines didn’t give it enough time to organize a vote by its members.
Boeing denied that it had not informed IAM representatives of the proposal, and said it would provide the union with more time and logistical support to vote with its members.
More than 30,000 Boeing workers have been on strike since September 13 after rejecting an offer of a 25% pay hike.
Members of the union – which builds planes including the 737 Max and 777 – voted overwhelmingly to reject the offer and support a strike until an agreement was reached.
The IAM initially aimed for a number of reforms in the workers' package, including a 40% wage increase.
The strike threatens to cost Boeing billions of dollars in losses, further deepening the crisis for a company already facing serious challenges.
The company has already suspended jobs of thousands of employees.