Safeway employees at a Denver store walked out Monday, expanding a strike that started this weekend. The strike started small with workers at three stores in Estes Park, Fountain and Pueblo, and a Denver distribution center.

Safeway workers voted to authorize a strike if the union gives 72 hours' notice, while an agreement with King Soopers to pause a strike expires Sunday.

With the clock winding down toward Saturday night's deadline for new contract negotiations, a Colorado union has announced locations where grocery employees are set to walk off the job on Sunday in protest.

Another grocery worker strike is in the works after UFCW Local 7 workers at Safeway and Albertsons Companies voted overwhelmingly in favor of the action — some stores voting unanimously in favor