The U.S. military operation that left elusive ISIS leader Abu Bakr al-Baghdadi without a head also succeeded in decapitating the organizational structure of the international terror group, which now faces a leadership vacuum in what is only the latest of several major setbacks.

In the aftermath of the weekend raid that cost ISIS its leader, the terror group was hit with another loss almost immediately.

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Abu Hassan al-Muhajir, a possible successor to al-Baghdadi who was known as the self-styled "Caliph's" right-hand man and ISIS spokesman, was killed in Aleppo province in a separate attack by U.S. forces, a senior State Department official told Fox News.

Al-Baghdadi was killed in the blast from his suicide vest during a U.S. Special Operations forces raid Saturday night. (AP/Al-Furgan media)

While it remains unclear who exactly will take over the terror organization, President Trump said in March the caliphate was “obliterated” and the U.S. will “continue to pursue the remaining ISIS terrorists to their brutal end.”

“We know the successors,” Trump said Sunday during a news conference following the al-Baghdadi raid. “And we’ve already got them in our sights.”

Read on for a list of those who could likely succeed al-Baghdadi as the head of ISIS.

Abu Othman al-Tunsi

Abu Othman Al-Tunsi, a Tunisian national, is head of the terror group’s Shura Council, a legislative body, Hisham al-Hashimi, an Iraqi expert on ISIS, told Agence France-Presse.

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Little else is known about al-Tunsi.

Abu Saleh al-Juzrawi – also known as Hajj Abdullah

Abu Saleh Al-Juzrawi, a Saudi who also goes by the name Hajj Abdullah, is in charge of the organization’s governing body, called the Delegated Council, Aymenn Jawad Tamimi, an academic and ISIS expert told AFP.

"He turns up in leaked IS documents as a deputy of al-Baghdadi and to my knowledge, he is not dead," Tamimi said, adding that not much is known about the possible successor.

However, since both al-Tunsi and al-Juzrawi are neither Syrian nor Iraqi, nationalities that make up a majority of the terror group’s guerrilla forces, choosing them may prove controversial and result in defections, according to the experts.

Abu Abdullah Qardash – known as 'the Professor' and 'the Destroyer'

Al-Baghdadi was believed to be preparing Abu Abdullah Qardash to lead ISIS, handing over more and more power to the former officer of Saddam Hussein, the Times of London reported in August.

Qardash and al-Baghdadi were both held at the Camp Bucca detention center in Basra after U.S. forces took them prisoner over their ties to Al Qaeda in 2003, according to the paper.

Qardash is reportedly known as “the Professor” and “the Destroyer.” (Handout)

He was already running the day-to-day operations before al-Baghdadi’s death, a regional intelligence official told Newsweek Sunday.

"Baghdadi was a figurehead. He was not involved in operations or day-to-day," the official said. "All Baghdadi did was say yes or no—no planning."

Rumors that al-Baghdadi had named Qardash as his successor stemmed from a months-old statement released by ISIS’ official Amaq news outlet, according to the AFP. Both Hashimi and Tamimi called the statement fake.

Furthermore, Qardash is believed to have been dead since 2017, Hashimi told the outlet, citing Iraqi intelligence sources.

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The terror group has yet to officially name a successor.

The void in leadership is the latest significant setback for the terror group after having already lost vast stretches of its physical caliphate that stretched across parts of Syria and Iraq. But counterterrorism experts have cautioned that they expect the group's ideology to endure beyond al-Baghdadi.

Fox News' Nick Kalman and The Associated Press contributed to this report.