However, officials told the Washington Post that Deputy Secretary of Defense David Norquist could be the next White House target for dismissal.

House Armed Services Chairman Adam Smith said in a statement on Tuesday that the "gutting" of the department ought to "alarm" Americans.

"It is hard to overstate just how dangerous high-level turnover at the Department of Defense is during a period of presidential transition. The top policy professional in the Department resigning the day after the Secretary of Defense was fired could mark the beginning of a process of gutting the DoD — something that should alarm all Americans," he said.

In separate remarks, Smith, the Democrat representative for Washington, told Politico: "If this is the beginning of a trend — the President either firing or forcing out national security professionals in order to replace them with people perceived as more loyal to him — then the next 70 days will be precarious at best and downright dangerous at worst."