WASHINGTON — Acting Secretary of Defense Patrick Shanahan is withdrawing his nomination for the permanent position, President Donald Trump said Tuesday.

Trump announced the news in a tweet.

Shanahan isn't going forward with the confirmation process "so he can devote more time to his family," Trump's tweet said.

Shanahan, a former Boeing executive, has been acting defense secretary since the beginning of the year. He replaced Gen. James Mattis, who stepped down with fanfare in December: His resignation letter said Trump should have a defense secretary whose views align more closely with the president's beliefs.

Trump's Shanahan tweet added that Army Secretary Mark Esper would be tapped to be the acting defense secretary.

"I thank Pat for his outstanding service," the president said. "I know Mark, and have no doubt he will do a fantastic job!"