The U.S. Department of Justice announced today that 9 more states have joined its antitrust lawsuit against Google. That brings the total number of U.S. states allied with the DOJ to 17.

“We look forward to litigating this important case alongside our state law enforcement partners to end Google’s long-running monopoly in digital advertising technology markets,” DOJ Principal Deputy Assistant Attorney General Doha Mekki said. “Today we welcome the States of Arizona, Illinois, Michigan, Minnesota, Nebraska, New Hampshire, North Carolina, Washington, and West Virginia who join our existing coalition of eight co-plaintiff states, to deliver the benefits of competition to website publishers, digital advertisers, and the American public.”

8 other U.S. states—California, Colorado, Connecticut, New Jersey, New York, Rhode Island, Tennessee, and Virginia—were already on board in an effort to prove that Google has abused its monopoly power in the online advertising business. The DOJ and states allege that Google’s ad business violates Sections 1 and 2 of the Sherman Act and they would like to see it divest itself of its Ad Manager suite, including the dominant DoubleClick service that the online giant acquired in 2008. Google now earns over 80 percent of its revenues from ads.

“The DOJ is doubling down on a flawed argument that would slow innovation, raise advertising fees, and make it harder for thousands of small businesses and publishers to grow,” Google noted of the suit back in January. Google asked a U.S. federal judge in late March to dismiss the lawsuit, but the additional support at the state level suggests that isn’t happening.