FIRST ON FOX: A House Republican lawmaker is introducing articles of impeachment against Defense Secretary Lloyd Austin, his office told Fox News Digital on Monday.

Rep. Matt Rosendale, R-Mont., plans to target Austin on Tuesday as fallout continues over the Pentagon’s delayed disclosure about Austin being hospitalized last week.

Rosendale told Fox News Digital in a statement that he believes Austin "violated his oath of office" on multiple occasions, citing the Biden administration’s withdrawal from Afghanistan, the migrant crisis at the border, and last year’s incident with a Chinese spy craft floating above the continental U.S.

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Secretary Lloyd Austin

A House Republican lawmaker is introducing articles of impeachment against Defense Secretary Lloyd Austin, shown. (Kevin Dietsch/Getty Images)

"Sec. Austin knowingly put the American people in danger and compromised our national security when he allowed a spy balloon from a foreign adversary to fly over Malmstrom Air Force Base – home to ICBMs – and allowed the Chinese Communist Party to gather intel on American citizens," the Montana Republican said. 

"This dishonesty seems to be a repeated pattern for the Secretary as he once again lied to our military and the American people about his health last week."

DEFENSE SECRETARY AUSTIN HOSPITALIZED FOLLOWING SURGERY COMPLICATIONS

Rep. Matt Rosendale

Rep. Matt Rosendale, shown, is filing impeachment articles against Defense Secretary Lloyd Austin. (Getty Images)

The Pentagon publicly revealed on Friday that Austin had been in the hospital since Jan. 1 due to complications from elective surgery. But a Politico report later revealed that not only were media kept in the dark, but that the highest levels of the White House and top officials in the Pentagon itself were not aware until Thursday that Austin was in the hospital.

The non-disclosure prompted a flurry of bipartisan concern, with top Democrats and Republicans on the House and Senate Armed Services committees both calling for more transparency about the incident.

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Secretary of Defense Lloyd Austin hosts an observance ceremony at the National 9/11 Pentagon Memorial on Sept. 11, 2023. (AP/Manuel Balce Ceneta)

Rosendale’s Monday evening statement went beyond the health scandal, arguing that Austin "failed to uphold his oath of office during the Biden Administration’s disastrous withdrawal from Afghanistan which led to the death of 13 American soldiers and enabled unvetted migrants to flow into the United States."

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"Sec. Austin is unfit for the Office of the Secretary of Defense, which is why I urge my colleagues to join me in impeaching him to protect the American people," he said.

A host of top Republicans have called for Austin to be fired over how the disclosure of his hospitalization was handled.

Fox News' Liz Friden contributed to this report.