The US Justice Department opened an investigation of Live Nation Inc.’s proposed merger with Ticketmaster Entertainment Inc., in the first test of the Obama administration’s antitrust policy.

The agency “is committed to vigorous enforcement of the merger antitrust laws and will conduct a thorough investigation,” Justice Department spokeswoman Gina Talamona said.

The review gives the Obama administration an opening to set the tone for evaluating transactions that raise concerns over market power.