WASHINGTON — President-elect Joe Biden announced late Tuesday that retired Army Gen, Lloyd Austin will be nominated to serve as the 28th United States Secretary of Defense.

If confirmed by the Senate, Austin, also former commander of US Central Command, would be the first Black man to lead the Department of Defense.

"I know Gen. Austin. I trust him. Because I know how he reacts under pressure," Biden tweeted. He added, "When (IS) emerged as a terrorist threat, President Obama and I turned to Gen. Austin in the Situation Room and he led us through. Now, I turn to him again as Secretary of Defense."

President-elect Joe Biden has selected Retired Gen. Lloyd Austin to serve as secretary of defense, according to three people with knowledge of the decision. If confirmed, Austin would be the first Black person to lead the Pentagon.

Austin emerged as a top-tier candidate in recent days after initially being viewed as a longshot for the job. Michèle Flournoy, Obama’s former Pentagon policy chief, was initially viewed as the frontrunner, but her name was notably absent from Biden’s rollout of key members of his national security team two weeks ago.

"Gen. Austin is a southerner, has impeccable credentials given his military career and would be an outstanding secretary for the department,” Rep. Bennie Thompson (D-Miss.), a CBC member who is close to Biden, told POLITICO earlier Monday.

A person familiar with Biden’s decision said the president-elect chose Austin because he is crisis-tested and respected across the military. Biden also trusts Austin, as they worked together when Biden served as vice president and had a large foreign policy portfolio.

The president-elect was also drawn to the history-making aspect of Austin’s nomination and his deep logistics experience, which will prove critical as the military helps distribute coronavirus vaccines, the person said.

Austin’s nomination may run into trouble on Capitol Hill. Austin has not been out of the military for the required seven years and would need a waiver from Congress to become secretary of Defense — and lawmakers have signaled their wariness of granting yet another exception for a retired general to lead the Pentagon just four years after President Donald Trump sought one for his first defense secretary, Jim Mattis.

Austin’s candidacy has also been met with resistance from some national security experts, who expressed concern about the balance of civil-military power in the Pentagon under yet another retired general. — Agencies