Workers at certain Safeway and Albertsons locations will begin striking on Sunday, in protest of what workers say are unfair labor practices, short-staffed stores, and frozen wages.

The union that represents 7,000 Safeway/Albertsons employees in Colorado terminated its contract extension with the company on Wednesday.

Safeway workers could strike as early as Sunday after the union gave 72-hour notice following stalled negotiations over staffing and unfair labor practices.

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.

Safeway workers are striking at the same time as contract negotiations between workers and King Soopers are coming to a head. The union is negotiating with King Soopers and parent Kroger after a strike in February. That strike lasted almost two weeks before a deal was reached to pause the labor action for 100 days. That pause expired last month.

Without a labor agreement in place with Union UFCW Local 7, Estes Park Safeway employees will go on strike on Sunday morning, joining just three other Safeway locations,