(Reuters) -Boeing Defense and the machinists' union remained at loggerheads after meeting on Tuesday in an effort to resume contract negotiations as a strike by about 3,200 St. Louis-area workers that assemble military aircraft enters its sixth week. 

Talks that included a federal mediator ended after a few hours, with both the company and the International Association of Machinists and Aerospace Workers (IAM) saying the other side was unwilling to move forward.  

"It became clear to the bargaining committee that the company wasn't serious about finding a way to end the strike," IAM officials said in a message to members of District 837.

Boeing Defense Vice President Dan Gillian said in a statement that "the union continues to ask for more of everything, which we've repeatedly told them is not constructive."

The strike began on August 4 after District 837 members rejected Boeing's latest four-year contract offer that included a 20% general wage increase. 

The company said its "focus is on executing our strike contingency plan" to maintain production at its St. Louis-area facilities. The plan includes hiring permanent replacement workers, Boeing said this month.

Gillian previously acknowledged that the strike has slowed work on some programs, which include its F-15, F/A-18, a military trainer jet, the MQ-25 military drone and munitions, among other work. 

Boeing's defense division has invested billions of dollars to expand manufacturing facilities and engineering capabilities in the St. Louis area for the new U.S. Air Force fighter jet, the F-47A. It won the contract this year.

The company is also competing to win the contract for the U.S. Navy's new fighter program, the F/A-XX.