CAMBRIDGE, Mass. (AP) — The American Postal Workers Union is calling upon Harvard University’s president to oppose a deal between Staples Inc. and the U.S. Postal Service, or resign her seat on the office supply company’s board.

Staples, based in Framingham, began providing postal services at some of its stores last year, under a partnership with the financially-struggling Postal Service.

“We’re not talking about just selling stamps,” union President Mark Dimondstein said in a statement. “Staples is pretending to be a post office, using low-wage, poorly-trained workers in an environment with weak security. Mail handled by Staples isn’t even considered U.S. Mail until it is handed-off to a uniformed postal worker.”

The postal workers union said Harvard University President Drew Gilpin Faust earns over $300,000 a year as a Staples board member and should use her position on the board to push for an end to the deal, or resign from the company board. The union, which represents some 200,000 workers, wants service counters to be staffed by uniformed postal workers rather than non-union Staples staff.

Neither Faust nor Staples responded Wednesday to requests for comments.

The union took out a full-page advertisement Wednesday in the Harvard Crimson, the school’s student newspaper. The paid ad suggests that Faust’s affiliation with Staples “sullies” the Ivy League school’s reputation.

The ad says the deal will help turn stable postal worker jobs into “high-turnover, poverty wage” jobs and might lead to closing some post offices and the privatization of the Postal Service, an independent agency of the federal government.