SEATTLE (AP) — The union for Boeing's technical workers is planning its next move after they rejected a contract offer, splitting with engineers represented by the same union who approved the deal.

The Society of Professional Engineering Employees in Aerospace notified a federal mediator Wednesday to resume negotiations.

The union will survey members of the technical bargaining unit to determine their priorities, SPEEA said. They also voted Tuesday to authorize a strike, but a strike by the 7,400 technical workers is not imminent.

The 15,500 engineers who have a new four-year contract in place will play a supporting role in the talks.

The union had recommended rejection of the contract because it would not provide pensions to new employees. They would have a 401(k) retirement plan instead.

The Chicago-based aerospace company said the change was important to its future. The labor dispute continues as Boeing works to solve battery problems that have grounded its new 787s.

Boeing Commercial Airplanes President and CEO Ray Conner said that the company was pleased with the engineers' vote but "deeply disappointed" in the technical workers' rejection of what he called the company's "best and final" offer.

"The realities of the market require us to make changes so we can invest in new products and keep winning in this competitive environment," Conner said in his statement.

"That's why our proposal to move future hires to an enhanced 401(k)-style retirement plan is so important, as we have repeatedly emphasized over the course of these negotiations."

Washington Gov. Jay Inslee said he's concerned about the split vote and spoke to union and Boeing representatives, urging them to resume negotiations.

"We cannot overstate the importance of the aerospace industry to the economy of Washington," Inslee said in a statement. "There are more than 131,000 employees in aerospace-related companies working across the state, the vast majority of which are directly reliant on the Boeing Company."

The union's nearly 23,000 employees are mostly in the Puget Sound region.

The factory-floor assembly work is done by the members of the International Association of Machinists. The Machinists approved a new, four-year contract in December 2011.