Teamsters said its members voted in favor of a strike as they entered a final round of talks to reach a new contract ahead of a Jan. 31 deadline.

More than 18,000 Costco workers will be walking picket lines in less than two weeks if a labor dispute over wages and benefits is not resolved, according to the Teamsters union. Members voted by an 85% margin to authorize a strike when their current contract expires on Jan. 31, the union announced on Sunday.

A statement by King Soopers accused union negotiators of “stall tactics and creating uncertainty.” The company said its final offer included significant investments of up to a 6% increase in the first year of the contract and “promises to support, protect and invest” in employees’ interests.