American Axle & Manufacturing Holdings Inc. offered the United Auto Workers union a new labor proposal on Friday, with workers now into the sixth week of a strike.

Spokeswoman Renee Rogers confirmed on Saturday that American Axle had submitted an offer but would not release details. Negotiations are expected to continue through the weekend.

The offer comes after American Axle said earlier this week that there had been a slight improvement in UAW's offer since the last time they negotiated, however American Axle still expressed disappointment over it.

The all-in labor cost proposed by the UAW is still approximately 200% of the market rate of AAM's competitors in the United States automotive supply industry, American Axle said.

If the UAW continues to refuse to make realistic economic proposals, AAM will be forced to consider closing the facilities at issue, it said.

About 3,600 workers went on strike at American Axle starting on February 26.

American Axle makes propeller shafts for vehicles. Its principal customer is former owner General Motors.