Government shutdown updates: Leavitt says Trump exploring cutting aid to Portland

Secretary of Defense Pete Hegseth addressed his previous firings of a "number of senior officers" since he began working in his position, saying that "we all serve at the pleasure of the president."

"When in doubt, assess the situation, follow your gut, and if it's best for the military, make a change," Hegseth said.

He added that his rationale in making these decisions has been "straightforward."

Secretary of Defense Pete Hegseth told top-ranking generals and admirals that physical fitness tests and grooming standards will now be in place for men and women working in the Department of War, saying "the era for unprofessional appearance is over."

He said that seeing "fat troops" or "fat generals" is a "bad look" and is "not who we are."

Hegseth emphasized that if those working for the Pentagon do not meet those standards, "it's time for a new position, or a new profession."

When speaking to top-ranking generals and admirals at a meeting in Quantico, Virginia, Secretary of Defense Pete Hegseth said that the department "must prepare now" for war.

"The time is now," Hegseth said on Tuesday morning.

Hegseth also emphasized the importance of "peace through strength" and having the "right people and the right culture."

He added that the department is "clearing the way for leaders to be leaders."

"You might say we are ending the war on warriors," Hegseth said.

Senate Minority Leader Chuck Schumer late on Monday responded to a post from President Donald Trump, saying the president could "only throw tantrums" rather than negotiating a deal to avert a potential government shutdown.

"If you think your shutdown is a joke, it just proves what we all know: You can’t negotiate," Schumer said. "You can only throw tantrums."

The reply followed an earlier post by Trump that included a manipulated video featuring likenesses of Schumer and House Minority Leader Hakeem Jeffries.

Jeffries and Schumer met earlier Monday with Trump in the Oval Office as part of bipartisan talks seeking a deal to avert a shutdown, which would begin at midnight on Wednesday.

-ABC News’ Justin Gomez