The Trump administration has carried out sweeping changes atop the Defense Department’s civilian leadership structure, removing several of its most senior officials and replacing them with perceived loyalists to the President. The flurry of changes, announced by the Department of Defense in a statement roughly 24 hours after President Donald Trump fired Defense Secretary Mark Esper, have put officials inside the Pentagon on edge and fueled a growing sense of alarm among military and civilian officials, who are concerned about what could come next. Four senior civilian officials have been fired or have resigned since Monday, including Esper, his chief of staff and the top officials overseeing policy and intelligence. They were replaced by perceived Trump loyalists, including a controversial figure who promoted fringe conspiracy theories and called former President Barack Obama a terrorist. A senior defense official told CNN late Tuesday that “it appears we are done with the beheadings for now,” referring to the wave of ousted civilian leaders, including Esper. But the moves will likely only add to the sense of chaos within the Pentagon following Trump’s firing of Esper. The President jettisoned him two days after his Democratic opponent, Joe Biden, was projected as the winner of the presidential election, a conclusion that Trump has refused to accept. Concerns are growing that a chaotic transition period could undermine national security. While top officials have been dealing with Trump’s unpredictable decision making since he took office, the current level of uncertainty has risen steadily since the election.