FIRST ON FOX: Rep. Ronny Jackson, R-Texas, says Joint Chiefs of Staff Chairman Gen. Mark Milley should go to jail if the accusations that he pledged to give his Chinese counterpart advance notice of a U.S. attack are true.

Jackson told Fox News in an exclusive interview on Wednesday that he will be calling for an investigation into Milley over the Biden administration’s botched troop withdrawal from Afghanistan and the recent book accusations about the “secret” calls Milley made.

The Texas Republican said he had been floating the idea into an investigation into Milley since the general’s comments about critical race theory made headlines, though he says the need for an investigation is now much more urgent.

MILLEY SPOKESMAN DEFENDS CALLS WITH CHINA AS ‘VITAL’ TO ‘AVOIDING UNINTENDED CONSEQUENCES OR CONFLICT’

“We need him to step up to the plate and be responsible,” Jackson said of Milley. “They need to admit that they made mistakes and, as a result, he should do what he would expect any other military member under his control to do, that is to resign and to turn it over to somebody else and to let somebody else have the reins of leadership.”

“That was before,” Jackson continued, saying that the “recent story of Milley talking to key people in the Chinese military and giving them insight into what’s going on in the White House,” as well as telling his Chinese counterpart he would “give them a heads up and talk to them” if the U.S. was planning to go to war with China.

Jackson said the allegations go “beyond resignation,” adding that he does believe Milley should “resign immediately” and that there should be a “congressional inquiry” into what happened.

“And if this is true, he needs to be held accountable. And when I say ‘held accountable,’ I’m not talking about just resigning or quitting,” the Texas congressman said. “I’m talking about potentially going to prison if this is true. I mean, this is treason. These are high crimes.”

The congressman said he could not “fathom” how a member of the American military could “undermine the commander in chief” and put the country “at risk by telling the Chinese… that we will let them know what’s going on in the White House.”

“If that happened, we need to know about it and he needs to be put in jail,” Jackson added.

A former Trump-era senior Defense Department official told Fox News on Wednesday that the calls were not a secret and were civilian-led at the behest of former Defense Secretary Mark Esper to cool Chinese intelligence reports that the U.S. was gearing up for an attack.

The former official also noted that the top brass at the Pentagon often talk with their counterparts in China and Russia to dampen the possibility of miscommunications and misunderstandings that could lead to war.

“This was a civilian-led phone call done at Esper’s request,” another former senior U.S. official said, adding that civilians in the Pentagon were kept appraised of the situation.

Jackson reiterated that the consequences for Milley’s alleged actions would only come down “if this is true,” and that he and the GOP are looking to take a measured approach to what happened.

“I don’t know if it’s true or not, it’s being reported from a book,” Jackson said. “The stuff that’s coming out of the book is very concerning.”

“If Milley is actually telling his counterpart in the Chinese military that he will give them a heads up if we’re planning to go to war with them, that’s not acceptable on any front,” the congressman continued. “I mean, that’s not a matter of reassurance, that is unbelievably inappropriate and not in the best interest of this country.”

“If it was other, more benign conversations that were just trying to maintain relationships and to make sure nothing went awry, that’s a different situation,” he said, adding that the nation needs “the truth” about what happened in the phone calls.

Jackson also reiterated that the allegations, should they be true, are “treasonous” and said there are “many reasons” as to why Milley should no longer remain at his post.

Milley came under heavy fire this week after a new book alleged that he promised to warn his Chinese counterpart of any incoming war during the Trump administration.

CLICK HERE TO GET THE FOX NEWS APP

A senior Defense Department official pushed back on the report and told reporters on Wednesday that Milley’s message to his Chinese counterpart was in line with the Defense secretary’s message.

“Milley was absolutely not going rogue. Esper took the initiative on this in October, Esper asked his own policy folks to backchannel the message,” the official said. “Milley’s message followed Esper’s.”

Fox News’ Jennifer Griffin contributed reporting.

Houston Keene is a reporter for Fox News Digital. You can find him on Twitter at @HoustonKeene.