WASHINGTON (AP) — Sen. John McCain is warning the Trump administration not to nominate any more defense industry executives for senior Defense Department positions.

During a hearing on Thursday, McCain, the Armed Services Committee chairman, said he’s long had reservations about defense contractors filling out the Pentagon’s upper ranks. But McCain is indicating he’ll support the nomination of Raytheon Vice President Mark Esper who was selected in July to be Army secretary.

He tells Esper his concerns grew out of early consultations he had with the administration about potential nominations, including Esper’s and “a handful of others that were yet to be nominated.”

McCain says “it was then that I decided I couldn’t support further nominees with that background, beyond those we had already discussed.”

Esper has been Raytheon’s top lobbyist since 2010.