LOS ANGELES (AFP) - Nearly 27,000 members of Boeing's largest labor union are to go on strike after last-ditch contract talks failed on Friday, the US aviation giant and labor unions said. A statement from Boeing said mediated talks between the firm and the International Association of Machinists and Aerospace Workers (IAM) ended without agreement. The union vowed to strike from 12.01 am (0701 GMT) Saturday. "Over the past two days, Boeing, the union and the federal mediator worked hard in pursuing good-faith explorations of options that could lead to an agreement," Boeing Commercial Airplanes president Scott Carson said. "Unfortunately the differences were too great to close," he added. In a statement on its website, the IAM confirmed the strike would begin, flatly blaming Boeing for the failure of negotiations. "The strike will commence at one minute after midnight tonight," the statement said. "This company disrespected the process, bargained illegally and most of all, disrespected the finest aerospace workers anywhere on the planet by failing to meet your expectations. "Despite meeting late into the night and throughout the day, continued contract talks with the Boeing Company did not address our issues." Boeing meanwhile said non-IAM members were expected to report for work as normal. The aircraft said customers and their airplanes in service would continue to receive support during the work stoppage. The company would also deliver planes completed prior to the strike but does not intend to assemble airplanes during the shutdown. Boeing made a contract offer on August 28 providing employees with about 34,000 dollars on average in additional annual wages and incentive payments over a three-year period, including an overall 11 percent wage increase. The current contract expired Wednesday. However the IAM said Boeing must fix "takeaways" in its proposal and address the issues its members have identified: job security, medical coverage, wages and pension benefits. A strike could cost Boeing an estimated 120 million dollars a day in revenues at the company's current level of production, analysts at Jefferies investment bank said. It also could seriously clip the wings of Boeing in its fight with Europe's Airbus for dominance of the commercial aircraft skies. Both aviation giants are betting on new planes as key weapons in their battle for supremacy: Boeing with its 787 Dreamliner and Airbus's super-jumbo A380. Airbus, a subsidiary of the European Aeronautic Defence and Space Company (EADS), delivered its first A380 jet to Singapore Airlines a year and a half late, in October 2007, after it was delayed by problems including electrical wiring glitches. Already delayed by nearly two years, Boeing now plans the Dreamliner's first delivery in the third quarter of 2009, after pushing it back three times because of technical and supply problems. The 787 is a revolutionary aircraft built with lightweight plastic composites instead of aluminum to reduce weight, increase range and cut fuel consumption. Some 900 Dreamliners have been ordered since the plane was offered for sale in late 2003. But the plane's delays have sparked demands for compensation from disgruntled airline customers. In early August, Azerbaijan Airlines became the first airline to cancel an order, for one Dreamliner.