Five weeks after announcing his intent to nominate Acting Defense Secretary Patrick Shanahan for the top job at the Pentagon, President Donald Trump abruptly announced Tuesday that Shanahan was no longer under consideration, and would be replaced by the Secretary of the Army.

"Acting Secretary of Defense Patrick Shanahan, who has done a wonderful job, has decided not to go forward with his confirmation process so that he can devote more time to his family," the President said, announcing that Army Secretary Mark Esper would be named as the new Acting Secretary of Defense.

President Trump had announced on May 9 that he intended to nominate Shanahan to the post; he had been acting Secretary since the start of 2019, replacing former Secretary James Mattis, who resigned at the end of December.

The move by the President came hours after reports by news organizations that Shanahan's FBI background check had been delayed because of an issue involving a domestic dispute with his ex-wife in 2010.

Shanahan had been meeting with Senators in recent weeks as a prelude to his confirmation hearings - but no date for those hearings had been set by the Senate Armed Services Committee, and no formal nomination had been made by the President.

It had led to speculation that Shanahan's nomination could be in jeopardy.

The move comes at an awkward time for the Pentagon, as Shanahan had been serving as Acting Defense Secretary since January 1, after taking over for ex-defense chief James Mattis.

Mattis resigned at the end of 2018 after a dispute with President Trump over U.S. troop levels in Syria and Afghanistan.

It means the U.S. will go well over a half year without a Senate-confirmed Secretary of Defense, a point noted by lawmakers on Capitol Hill.

"This job should be filled in a matter of a few weeks, not months," said Rep. Mac Thornberry (R-TX), the top Republican on the House Armed Services Committee.

“We urgently need a Secretary of Defense that has the confidence of the President, the Congress, and the country,” Thornberry said.