Starbucks is asking the National Labor Relations Board to suspend all union elections at its U.S. stores. The request came Monday in response to a board employee’s allegations that regional NLRB officials improperly coordinated with union organizers. In a letter sent to the board, Starbucks said an unnamed career NLRB official told the company about the activity, which happened in the board’s St. Louis office in the spring while it was overseeing an election at a Starbucks store in Overland Park, Kansas. The labor board says it doesn’t comment on open cases. More than 220 U.S. Starbucks stores have voted to unionize since late last year. The company opposes unionization.