Washington • Sinclair Broadcasting’s proposed $3.9 billion acquisition of Tribune Media has raised “serious concerns” at the Federal Communications Commission about the amount of control the combined company would have over the U.S. television market, said Ajit Pai, the agency’s chairman.

Pai said Monday that he intends to send key parts of the deal to review by an administrative law judge, which is typically the first step the FCC takes when it seeks to block a deal.

The merger would consolidate Sinclair’s position as a major conservative broadcasting entity, adding dozens of media stations to its roster. Its original merger proposal, if approved, would have given Sinclair access to 72 percent of television households in America, far surpassing a national ownership cap of 39 percent.

Sinclair had proposed spinning off a number of stations to get beneath the cap. But a number of the new, prospective owners had close ties to Sinclair executives, which critics said would allow Sinclair to stay in control of the stations it sold.

Pai said Monday he found those arguments persuasive.

“The evidence we’ve received,” said Pai, “suggests that certain station divestitures that have been proposed to the FCC would allow Sinclair to control those stations in practice, even if not in name, in violation of the law.”