(Reuters) -The U.S. Department of Justice and a group of states will sue Live Nation Entertainment, potentially seeking a break up, Bloomberg News reported on Wednesday, outlining the next step in an antitrust campaign against the Ticketmaster owner.

The Justice Department has been investigating Ticketmaster's domination of concert ticket sales, sources have previously told Reuters. Concert fans and politicians for years have called for a re-examination of the Live Nation-Ticketmaster merger in 2010, especially after the botched sale of tickets to a Taylor Swift concert tour.

Bloomberg said the lawsuit is expected to be filed in the Southern District of New York on Thursday. 

The legal action underscores the aggressive approach President Joe Biden's antitrust enforcers have adopted as they seek to create more competition in a wide range of industries, from Big Tech to healthcare to groceries. It also shows the power and anger of concert-goers and Swifties, the nickname for Swift's fans.

Live Nation came under fire in 2022 after Ticketmaster mishandled the sale of tickets to Swift's 2023 tour. Ticketmaster was overwhelmed, canceling some plans for sales and sending would-be buyers into online queues for as much as eight hours.

Some Swifties said they were repeatedly dropped by Ticketmaster as they waited to buy. The service complained it was the target of bots and scalpers, but concert-goers also complained of high prices and poor service.

U.S. senators in January 2023, in a hearing called after the ticket sales fiasco, slammed Live Nation's lack of transparency and inability to block bot purchases of tickets. 

In the lawsuit to be filed on Thursday, the DOJ's options range from requiring the company to stop illegal behavior, a common request, to asking a court to break it up, which is rare. 

The lawsuit comes after the Justice Department in 2010 approved Ticketmaster's controversial merger with Live Nation, with conditions intended to stop the combined company from harming competition. 

In 2020, a court extended most of its oversight of the merger to 2025 because, the department said, Ticketmaster retaliated against stadiums and arenas that opted to use other ticketing companies. 

Live Nation did not immediately respond to a request for comment. It has said in the past that it was confident its business practices were legal, and that the probe had been prompted by complaints from rivals, including re-sellers. 

Live Nation's shares fell 7% in after hours trade. 

The Department of Justice did not immediately respond to Reuters' request for comment.