Sen. Al Franken is calling for the Justice Department to investigate whether Comcast broke antitrust laws by announcing who would manage NBC Universal before the Comcast-NBC merger was approved by federal officials.

Franken wrote a letter to the Justice Department Monday urging an antitrust inquiry into alleged "gun jumping," after Comcast named 43 individuals to NBC positions last Wednesday that would take effect once the merger was finalized.

"The Department of Justice and Federal Communications Commission have yet to complete their review of the proposed Comcast and NBC Universal merger," Franken wrote. "And yet, by publicly announcing their intended managers of each component of NBC Universal, Comcast has effectively told employees at NBC Universal who their 'real bosses' are."

Franken, who once worked for NBC on Saturday Night Live and as a producer, has been one of the biggest critics on Capitol Hill of the proposed Comcast-NBC merger. At a hearing earlier this year, he told executives that he didn't trust their promises.

In a statement responding to Franken's letter, Comcast said: "Transition and integration planning is common, proper, and expected in a transaction of this type. Post-closing management teams are regularly announced prior to antitrust approval."