Boeing Company's 27,000-strong machinists' union walked off the job on Saturday after the plane maker failed to improve its contract offer after two days of emergency talks.

At midnight, a crowd of more than 100 employees gathered near the entrance of Boeing's factory in Everett, Washington, whistling, honking and waving picket signs as the strike got underway. A small police presence ensured the scene was calm.

'Despite meeting late into the night and throughout the day, continued contract talks with the Boeing Company did not address our issues,' Tom Wroblewski, the IAM's Seattle-area president, said in a letter to members. 'The strike is on.'

The vast majority of the International Association of Machinists and Aerospace Workers' (IAM) members voted to reject Boeing's 'best and final' offer on Wednesday, but postponed a strike for 48 hours to give negotiators more time.

Boeing and IAM negotiators, along with federal mediators, met near Orlando, Florida in a last-ditch effort to hammer out an agreement.

'Over the past two days, Boeing, the union and the federal mediator worked hard in pursuing options that could lead to an agreement. Unfortunately the differences were too great to close,' said Scott Carson, the head of Boeing's commercial plane unit, in a statement.

No further talks are scheduled. Both sides said they were waiting for the other to make the first move. Boeing spokesman Tim Healy said the company was 'open' to hearing from the IAM.

'If this company wants to talk, they have my number, they can reach me on the picket line,' the IAM's Wroblewski said in a message to union members.-Reuters