(CBS News) — Add Apple to the list of major U.S. companies, including Amazon and Starbucks, facing an incipient push by workers to form a union.

At an Apple store in the Towson Mall near Baltimore, Maryland, labor organizers who have been mobilizing workers for about a year on Tuesday announced their wish to unionize in a letter to Apple CEO Tim Cook. Workers at two other of the $2.6 trillion company’s stores have also filed a petition with the National Labor Relations Board (NLRB) requesting a union vote.

READ MORE: Environmental group's annual sunscreen guide released

“To be clear, the decision to form a union is about us as workers gaining access to rights that we do not currently have,” the organizers, who call themselves the Coalition of Organized Retail Employees, or CORE, wrote in the letter.

They also asked the tech giant “to pledge not to use your resources to engage in an anti-union campaign to dissuade us. We ask that you voluntarily recognize our union so we can begin working together as equals in a spirit of cooperation and collaboration.”

READ MORE: Wingstop could soon raise its own chickens

The union drive comes after Apple workers at its Cumberland Mall location in Atlanta in April filed paperwork to hold a union election. Voting is scheduled to begin June 2. Workers at the iPhone maker’s retail store in New York’s Grand Central Terminal have taken the first steps to form a union in April.

Apple did not immediately reply to a request for comment.

MORE NEWS: Target Posts A Drop In Profit, Stock Plunges

Click here for more details from CBS News.