WASHINGTON (AP) — A federal judge has blocked the proposed merger of Staples and Office Depot, saying the government had made the case that the merger had a “reasonable probability” of hurting competition in office supplies.

The injunction issued Tuesday by U.S. District Judge Emmet Sullivan likely means the last two national office-supply chains will drop their $6.3 billion merger plan. The companies had said they would do so if the ruling went against them.

The Federal Trade Commission has sought to block the merger, contending it would allow the new combined company to dictate the price of supplies, especially for corporate customers that buy in bulk.