ISIS confirms death of Abu Bakr al-Baghdadi, announces new leader originally appeared on abcnews.go.com

ISIS has confirmed the death of its leader Abu Bakr al-Baghdadi on Thursday, four days after President Donald Trump said the terror chief killed himself in a suicide explosion during a U.S. raid to capture or kill him on Saturday.

But the terror group, which has lost territory the size of Britain to a global coalition led by the U.S., warns that its reach across the world will expand under a new leader, identified as Abu Ibrahim al Hashimi al Qurashi.

The message, from the terror group's new spokesperson Abu Hamza al Qurayshi, also confirms the death of Baghdadi's right-hand adviser and ISIS spokesperson Abu Hassan al-Muhajir, who was killed in a U.S. airstrike Sunday in Syria near the Turkish border, according to a senior State Department official.

(MORE: ‘It is going to become worse’: ISIS prisoner predicts attack on Europe after al-Baghdadi death)

PHOTO: An aerial view taken on October 27, 2019, shows the site that was hit by helicopter gunfire which reportedly killed nine people near the northwestern Syrian village of Barisha in the Idlib province along the border with Turkey. (Omar Haj Kadour/AFP via Getty Images, FILE) More

The death of the infamous leader, who attracted tens of thousands of fighters to the "caliphate" in Iraq and Syria, has been heralded by the Trump administration as a significant blow for ISIS, but the message says the group "stands at the threshold of Europe and Central Africa.... It is expanding and remaining, with permission from Allah, from the east to the west."

The speech provides little information about the new leader or spokesperson, with both names actually noms de guerre that mask their real identity, but tie them to the Quraysh tribe, a historic Arab tribe based near Islam's holy city Mecca. Doing so is a way to create legitimacy for their leadership because the prophet Muhammad is said to be from the Quraysh tribe.

(MORE: Pentagon releases video showing US special forces approaching al-Baghdadi compound)

The leadership council of ISIS "convened immediately" after Baghdadi's death and agreed to pledge allegiance to al Hashimi, who is described as an experienced and battle-hardened commander, a "scholar of its scholars," and devout cleric, according to a translation by SITE Intel Group.

Al Hashimi is also identified as a "caliph" -- meaning the group still considers itself a caliphate despite its loss of territory. Pledges to the new leader have come in across social media, according to analysts, who have warned that the terror group has fierce affiliates in West Africa, the Middle East, South Asia, and even Southeast Asia.

PHOTO: Late Islamic State leader Abu Bakr al-Baghdadi is seen in an undated picture released by the U.S. Department of Defense in Washington, Oct. 30, 2019. (U.S. Department Of Defense via Reuters, FILE) More

"Do not be happy O America, for the death of Sheikh al-Baghdadi, and do not forget the cups of death at his hands," Abu Hamza warns, adding in a shot at Trump: "Do you not look how at how you have become the joke of the nations, your fate controlled by a stupid old man, who goes to sleep with one opinion and wakes up with another?"

There are also some 10,000 fighters still detained in prisons guarded by Syrian Kurdish forces allied with the U.S. in Syria. The security of those prisons is tenuous, with over 100 of them escaping in recent weeks after Turkey's offensive against the Kurds and U.S. officials warning for months that something must be done to repatriate fighters to their home countries and deal with the majority -- 8,000 or so -- that are from Iraq and Syria.

(MORE: Why ISIS leader and founder Abu Bakr al-Baghdadi's remains were buried at sea)

Neither the White House nor the State Department has responded to questions about the message.

"We killed the last murderous bastard who ran ISIS. Let's go get the next one," said Sen. Ben Sasse, R-Neb., in a brief statement.