OTTAWA -- Canada's competition commissioner has dropped its challenge of a proposed merger between Staples and Office Depot, which was scrapped last week by the two U.S. multinational companies after an American judge blocked the plan.

Both Canada's Competition Bureau and the U.S. Federal Trade Commission had challenged the proposal, arguing it would harm competition in the office products business.

U.S. district judge Emmet Sullivan ruled on May 10 that the FTC had demonstrated that the merger would "substantially impair" competition as a supplier to large business customers.

Staples and Office Depot said they wouldn't appeal the ruling and they dropped the merger plan the same day.