Former President Trump announced Friday night that he has agreed to Fox News' proposal for a debate against Vice President Kamala Harris.

Trump said the debate would be held on Sept. 4 in Pennsylvania, although the location of the event has not yet been determined.

The former president also noted that an ABC News debate previously scheduled against President Biden before he suspended his re-election campaign had been canceled, citing his lawsuit against that network and one of its hosts, George Stephanopoulos.

"I have agreed with FoxNews to debate Kamala Harris on Wednesday, September 4th," Trump wrote on his social media platform Truth Social. "The Debate was previously scheduled against Sleepy Joe Biden on ABC, but has been terminated in that Biden will no longer be a participant, and I am in litigation against ABC Network and George Slopadopoulos, thereby creating a conflict of interest."

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The moderators of the debate will be Fox News anchors Bret Baier and Martha MacCallum.

The debate rules will be similar to the rules of the June 27 CNN debate against Biden, who Trump wrote "has been treated horribly by his Party." But unlike the CNN debate, which did not have an audience, the Fox News debate will have spectators.

Fox News had invited Trump and Harris to participate in a debate in Pennsylvania on Sept. 17.

Harris said last month that she was "ready" to debate the former president and accused him of backpedaling away from the previous agreement to debate on ABC News on Sept. 10.

This comes after Harris became the Democratic Party's nominee for president after Biden announced he was dropping his re-election campaign.

Trump previously said he would not debate Harris because she was not the party's official candidate after Biden dropped out of the race. But on Friday, the vice president secured enough delegates to officially become the party's nominee.

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"As everyone knows, the Democrats have Unconstitutionally taken a Candidate, who was acknowledged to be defeated, and unceremoniously replaced him with a new Candidate," Trump wrote. "This has never been done before, and is a Threat to Democracy, but I am totally prepared to accept the results of this 'coup,' and replace Joe on the Debate stage with Crazy Kamala Harris."

"I spent Hundreds of Millions of Dollars, Time, and Effort fighting Joe, and when I won the Debate, they threw a new Candidate into the ring. Not fair, but it is what it is!" he continued. "Nevertheless, different Candidate or not, their bad Policies are the same, and this will be strongly revealed at the September 4th Debate. I look forward to meeting and debating Kamala Harris on September 4th. This date is convenient and appropriate in that it is just prior to the September 6th start of Early Voting in the 2024 Presidential Election. I look forward to seeing everyone on September 4th, in the Great Commonwealth of Pennsylvania!"

Trump also survived an assassination attempt at a campaign rally in Pennsylvania on July 13.

A stunning backtrack Friday on the plea deal that Pentagon prosecutors agreed to with three of the terrorists behind the Sept. 11 terror attacks who were awaiting trial in Guantánamo Bay, Cuba.  

The deal that stirred national outrage and took the death penalty off of the table has been revoked by Defense Secretary Lloyd J. Austin III in a terse memo. 

Secretary Austin III is now taking the lead on the case for 9/11 mastermind Khalid Shaikh Mohammad, Walid Muhammad Salih Mubarak Bin 'Attash, and Mustafa Ahmed Adam al Hawsawi.

In his order, Austin relieved the official in charge of the military commission who had signed off on the original plea deals.

"Effective immediately, in the exercise of my authority, I hereby withdraw from the three pretrial agreements that you signed on July 31, 2024," the letter from the Secretary of Defense reads. 

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No explanation was given on why this was not settled earlier before the deals were signed off and publicly released.

The powerful House Armed Services Committee announced earlier Friday it was launching an investigation into the plea deals, which Chairman Mike Rogers, R.-La., called "unconscionable."

"I, along with much of our nation and Congress, are deeply shocked and angered by news that the terrorist mastermind and his associates who planned the September 11, 2001 terror attacks, which killed nearly 3000 innocent people, were offered a plea deal," Rogers wrote in the letter, first obtained by Fox News Digital. Rogers called news of the deals a "gut punch" to victims' families.

On Thursday, after news of the widely criticized deals broke, the White House claimed that President Biden "played no role" in the process.

"The White House learned yesterday that the Convening Authority for Military Commissions entered into pretrial agreements, negotiated by military prosecutors, with KSM and other 9/11 defendants," a White House National Security Council spokesperson told Fox News Digital. "The President and the White House played no role in this process. The President has directed his team to consult as appropriate with officials and lawyers at the Department of Defense on this matter." White House national security spokesman John Kirby reiterated that the White House played no role in the plea deal on Fox News Channel, adding that the administration was "not aware" of the deals until they were announced.

The president rejected a proposal last year that would have spared the three suspects from the death penalty.

Victims' groups have been swift to respond both the deal, and the swift about face move from Austin, revoking it. Patrick Hendry, president of the Police Benevolent Association of the City of New York, told Fox News that this was a big relief for the families of victims of the 9/11 terror attacks. "The families of our 9/11 heroes channeled their anguish and outrage into a powerful message. It’s thanks to their courage that these shameful plea agreements have been reversed. We are relieved and grateful, but the job is not done yet. As we have said from the beginning, these terrorists who claimed so many innocent lives should receive the ultimate punishment. The safety of our nation demands it, and the long-suffering families of the fallen deserve nothing less."

"We are astounded and deeply frustrated that our families were not consulted or even notified in advance of the plea deal or its subsequent revocation," said 9/11 Justice President Brett Eagleson. "These monsters need to be forced to share every piece of information they have about the attacks and be held fully accountable for the murder of our loved ones. It's not just about punishment, it's about uncovering the full truth.

"Our quest for truth and justice remains unwavering. We demand that the administration ensures these individuals provide vital information regarding the 9/11 attacks, including the extent of the Kingdom of Saudi Arabia's involvement. The American people and the families of the nearly 3,000 victims deserve to know every detail. This decision should not hinder our efforts to hold those responsible, including the Saudi government, accountable for their roles in this horrific tragedy.

"9/11 Justice will continue to fight relentlessly until we uncover the full truth and secure justice for the victims and their families. The revocation of these plea deals must lead to greater transparency and accountability, ensuring that no stone is left unturned in our pursuit of justice."

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The defendants are accused of providing training, financial support and other assistance to the 19 terrorists who hijacked passenger jets and crashed them into the World Trade Center in New York City, the Pentagon in Arlington, Virginia, and a field in Shanksville, Pennsylvania, on Sept. 11, 2001.

The attacks killed nearly 3,000 people in the worst terror attack on U.S. soil in American history. Loved ones of the victims expressed outrage upon hearing news of the deal. 

Fox News Digital reached out to the White House for comment. 

Fox News' Bryan Preston contributed to this report.