The Department of Justice's antitrust chief today offered another reminder that there's a new sheriff in town, and that this administration is going to take a much more active role in policing markets to keep them competitive.

The DoJ today said that it is requiring AT&T to divest the assets of Centennial in eight markets in Mississippi and Louisiana where the two firms are the primary wireless provider. The agency sued to block AT&T's $944 million acquisition of the smaller provider as originally proposed, but offered the alternative settlement to address the competition concerns.

"These divestitures are necessary to preserve the benefits of competition for wireless customers in these areas of Louisiana and Mississippi," Christine Varney, the assistant attorney general who heads the antitrust division, said in a statement.

The move is the latest signal that firms can expect closer scrutiny by the nation's consumer protection agencies, particularly when it comes the wireless sector, which has already come under the microscope at both the Federal Communications Commission and the DoJ.

The DoJ's filed its lawsuit jointly with the Louisiana attorney general.