Staffers working for the antitrust division of the Department of Justice have recommended the agency sue to block the merger of T-Mobile and Sprint, arguing it will reduce competition and raise prices for consumers.

Two sources familiar with the matter told CNBC staffers have been skeptical of the merger and recommended blocking it on antitrust grounds. But the final decision will rest with President Donald Trump’s political appointees, notably Makan Delrahim, who heads the antitrust division. Delrahim can agree, modify, or reject the staffers’ recommendations.

The disclosure hammered Sprint shares earlier this morning in pre-market trading. Wall Street analysts are likely experiencing significant headaches trying to predict where the deal will ultimately end up. Earlier this week, the FCC’s Republican majority signaled they were prepared to approve the merger, based on concessions including the spinoff of prepaid Boost Mobile, which resells Sprint service.

A final decision from the Justice Department is likely to be announced in June.