Safeway workers in several Colorado cities entered the third day of labor strikes Tuesday against Safeway and Albertsons over alleged unfair labor practices, with picketing in Grand Junction prompting a temporary store closure.

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.

Currently, unfair labor practice strikes are limited to Safeway/Albertsons locations in just four cities: stores in Estes Park, Fountain and Pueblo, and a distribution center in Denver.

Safeway and Albertsons employees across Colorado hit the picket lines this weekend, protesting what they say are unfair labor

The union representing Safeway store employees in Colorado has given the required 72-hour notice that the strike is set to begin one minute before midnight on Sunday.

The officials of the United Food and Commercial Workers are deliberately isolating different sections of grocery workers to keep a national movement from emerging.