Contract talks between the United Auto Workers and auto makers intensified Tuesday as agreements covering 407,000 workers were due to expire at midnight.
The union, which has said little about the progress of the talks, appeared to be negotiating hardest with DaimlerChrysler. Officials met at the German auto maker's U.S. offices in Auburn Hills late into Monday night and resumed talks early Tuesday.
While UAW President Stephen P. Yokich has praised DaimlerChrysler's offers, there were signs the union was prepared to fight. Workers on the second shift at two plants in Fenton, Mo., outside St. Louis, walked off the job about 9:45 p.m.
DaimlerChrysler spokesman David Barnas said the union has not given a reason for the walkout. The plants employ about 7,100 workers. Barnas said he was unsure how many were on the job when the walkout took place. Officials at both local unions could not immediately be reached for comment.
Officers at local unions in Detroit and Warren, Mich., also said they were preparing to walk out at midnight if a contract extension was not granted.
Earlier in the day, DaimlerChrysler Co-Chairman Robert Eaton said talks were proceeding, but that wages and job security issues were still on the table.
"The negotiations are proceeding very, very well . . . but it isn't over till it's over, and we'll all just have to wait and see," Eaton told cable financial network CNBC in an interview Tuesday morning from Frankfurt, Germany, where he was attending an industry trade show.
Negotiations were also underway with General Motors Corp. and Ford Motor Co. UAW negotiators met at GM during the weekend, but did not meet at Ford.
In the past, the union has extended contracts past the deadline. Ford spokesman Ed Miller said the UAW had indefinitely extended Ford's contract Tuesday.
An extension has yet to be arranged for DaimlerChrysler or GM, but experts said a strike that would threaten a boom year for the auto industry seems unlikely. The UAW has not called a national strike during contract negotiations since 1976.
The UAW usually chooses one auto maker to make a deal with first, then uses that deal as a template for other contracts. This year, Yokich has kept talks going with both GM and DaimlerChrysler and refused to publicly name a target.
Both sides have released little information about the talks. Wages, job security, health-care costs, overtime demands and the assignment of work to outside suppliers were expected to be among the top issues in this year's talks, as they were during the last round, in 1996.