Boeing workers at three United States facilities that produce military aircraft and weapons have voted to reject the company’s latest contract offer, opting to continue their nearly three-month-long strike.

The strike, involving about 3,200 machinists at plants in Mascoutah, Illinois, and the Missouri cities of St. Louis and St. Charles, is smaller than last year’s walkout by 33,000 commercial jetliner assemblers but poses new challenges to Boeing’s efforts to restore its financial stability.

“Boeing claimed they listened to their employees – the result of today’s vote proves they have not,” Brian Bryant, president of the International Association of Machinists and Aerospace Workers, said in a statement.

Boeing expressed disappointment over the outcome, noting that the vote was narrowly decided.

In a statement, the company said it had been hearing from a growing number of employees “who want to cross the picket line” and “recognize the value of our offer.”

“The union’s statement is misleading since the vote failed by the slimmest of margins, 51% to 49 per cent,” Boeing said.

“We are turning our focus to executing the next phase of our contingency plan in support of our customers.”

The machinists’ union also noted that the vote was close but told members in a message that “very few” workers have crossed the picket line.

“Our solidarity remains strong, and the company’s claim otherwise is wrong,” the union said.

Union leaders said negotiations have reached an impasse over wages and retirement benefits, while Boeing maintains that the workers’ demands go beyond the region’s cost of living.