Acting Secretary of Defense Patrick Shanahan will step down on June 23, handing Secretary of the Army Mark Esper the reins to the Pentagon.

"The Acting Secretary will resign as Deputy Secretary of Defense effective midnight, June 23," the Pentagon said in a statement Tuesday, "Secretary of the Army Esper will become the Acting Secretary of Defense immediately thereafter."

The transition of power came after U.S. President Donald Trump said Shanahan had withdrawn his nomination as the secretary of defense, citing family issues. Trump tweeted that he will appoint Esper to be the acting defense chief.

Speaking to the press after the announcement, Trump said he will "most likely" nominated Esper for the top defense job.

"Most likely. That's what I'm thinking about doing. And pretty soon," he said, "He's very experienced. He's been around all of the things that we're talking about for a very long period of time."

Esper, who graduated from West Point and served in the U.S. Army during the Gulf War, saw his career span across think tanks, the executive branch and the U.S. Congress. He was hired by defense contractor Raytheon in 2010. Esper assumed his current role in November 2017.

U.S. press noted that Tuesday marked the 168th day for which the post of the secretary of defense is vacant. Previously the longest stretch of vacancy was about two months.