BALTIMORE (WJZ) — Maryland Attorney General Brian Frosh is joining a number of other attorneys general in a lawsuit seeking to block the merger of cell phone providers Sprint and T-Mobile.

Nine states and the District of Columbia are suing the telecom companies, saying the merger would reduce competition and drive up prices.

In a statement announcing the state’s participation in the lawsuit, Frosh called the combination of the nation’s third-largest and fourth-largest wireless carriers “dangerous for consumers.”

The companies have argued the merger is necessary to take on larger rivals AT&T and Verizon and would help speed up deployment of faster 5G service.

Both companies’ stock prices dropped Tuesday following news of the lawsuit.

Attorneys general in California, Colorado, Connecticut, Michigan, Mississippi, New York, Virginia and Wisconsin are all plaintiffs in the suit.