The U.S. Justice Department has a team of litigators prepared to oppose the merger of ticketing giant Ticketmaster and concert promoter Live Nation and could decide to take the deal to court, antitrust sources said on Wednesday.

The DOJ has had a litigation team preparing the case for litigation for months, one antitrust source said, adding that publication was inaccurate in reporting that the Justice Department was prepared to approve the deal.

From the best we can tell, no decision has been made, said a second antitrust source. We have the impression that efforts to settle have fallen through.

Shares of both Ticketmaster and Live Nation opened higher on report, but later slid back somewhat on news of potential Justice Department opposition.

Ticketmaster shares were up 4.7 percent at $14.33 on Wednesday afternoon after peaking at $15.02 earlier in the session. Live Nation was up 6.4 percent at $9.95 after jumping as high as $10.28.

Live Nation is the world's largest concert promoter, while Ticketmaster is the leading ticketing group.

Neither Ticketmaster nor Live Nation was immediately available for comment.

In February, Live Nation announced plans to buy Ticketmaster Entertainment for about $400 million in stock, drawing almost immediate criticism from some U.S. politicians and artists who felt the combined group would have unrivaled power over music fans and the prices they would have to pay.

Last month, the deal got a boost when British antitrust regulators dropped objections and approved it.

Live Nation executives said in November that they expected the deal to close in the first quarter of 2010.

(Reporting by Diane Bartz, editing by Maureen Bavdek and Lisa Von Ahn)