By Daniel Wiessner

(Reuters) – Starbucks Inc (NASDAQ:) filed complaints Wednesday with a U.S. labour board alleging that a national union representing cafe worker’s in the United States had intimidated and bullied workers and customers. This was in violation federal law.

Starbucks filed two complaints with the National Labor Relations Board alleging that Workers United engaged in illegal conduct at demonstrations in Phoenix (Arizona) and Denver (Colorado).

Workers United filed petitions for representation of Starbucks employees at approximately 200 U.S. stores and won around two dozen elections from December.

Starbucks complained that union organizers had blocked entrances to and exits from stores, threatened customers and shouted obscenities during protests.

The company filed complaints stating that Workers United and its agents “have jeopardized personal safety, caused severe distress and illegally interfered in business operations.”

Workers United, an affiliate to the Service Employees International Union said that the complaints were a result of Starbucks’ despair as workers try to form unions.

Workers United filed over 80 complaints against Starbucks with the NLRB, accusing them of using illegal union-busting tactics like threatening or firing workers. Starbucks denied any wrongdoing.

Rossann Williams is the executive vice president of Starbucks. A letter that Reuters received from employees stated that Starbucks filed the complaints in order to protect “the physical safety and the emotional well-being of our partners, and to make it clear that we don’t accept the behaviour we see coming from union organizers.

A nationwide campaign to unify Starbucks stores forms part of an increase in petitions for union elections filed in the United States over the past six months. For the first time, unions have organized warehouse workers at Amazon.com Inc (NASDAQ) and retail employees at Apple Inc (NASDAQ)