Workers at Starbucks locations in the metro area and Duluth have joined a nationwide strike. Starbucks Workers United — which represents workers at more than 500 stores across the country — recently authorized an unfair labor practices strike, with workers walking off the job on Christmas Eve.

Starbucks' union says workers are walking off the job at some 300 — out of over 10,000 — stores across the U.S. as contract negotiations falter. The company urges it to return to the bargaining table.

The union representing Starbucks workers said its five-day strike will conclude on Tuesday with the strike spreading to more than300 stores, adding more establishments in metro areas.

In what the union has dubbed "The Strike Before Christmas," more than 5,000 workers are walking out of 300-plus Starbucks locations nationwide Tuesday.

Starbucks baristas' fast-growing unfair labor practice strike is expected to hit historic levels Tuesday as hundreds of stores nationwide prepare to join walkouts at the coffee giant. The Starbucks Workers United strike,

Starbucks Workers United told USA TODAY that employees in Boston, Dallas-Fort Worth, and Portland, Oregon also joined picket lines.

More than 5,000 workers were expected to take part in walkout that ends later on Christmas Eve, their union says.