Teamsters said on Sunday its members at U.S. retailer Costco Wholesale voted in favor of a nationwide strike, as they entered a final round of talks to reach a new contract ahead of a Jan. 31 deadline.

Costco workers affiliated with the Teamsters have voted in favor of going on strike if no deal is made ahead of a January 31 contract deadline.

The union representing 18,000 Costco workers says executives at the warehouse retailer “abruptly ended” collective bargaining negotiations last week.  “

The Costco Teamsters represent more than 18,000 workers nationwide.