ISIS is mourning the death of its leader Abu Bakr al-Baghdadi and has announced a successor in a new audio release. The group identified the new leader as Abu Ibrahim al-Hashimi in the audio released Thursday by the ISIS central media arm, al-Furqan Foundation.

The speaker in the audio also confirmed the death of Abu Hassan al-Muhajir, a close aide of al-Baghdadi and a spokesman for the group. On Tuesday, President Trump said al-Muhajir has been "terminated by American troops."

Al-Muhajir was killed in a joint U.S. operation with Kurdish forces in Jarablus, in northern Syria on Sunday, hours after al-Baghdadi blew himself up during a U.S. raid in Syria's northwestern Idlib province.

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The new spokesman, named Abu Hamza al-Qurayshi, urged followers to pledge allegiance to the new Caliph and addressed the Americans, saying: "Don't rejoice."

"The Shura Council met immediately after confirming the martyrdom of Sheik Abu Bakr al-Baghdadi. The leaders of the Mujahedeen agreed after consultation with their brethren and acting according to the will (of al-Baghdadi) they pledged allegiance to Abu Ibrahim al-Hashimi al-Qurayshi as the new leader of the Believers."

The new Caliph is identified as a scholar, a well-known warrior and "emir of war" who has battled American forces and knows "its wars."

"So don't rejoice America for the death of Sheik al-Baghdadi," the speaker said. "Don't you know America that the state (IS) today is at the doorstep of Europe and is in Central Africa? It is also expanding and remaining from east to west." The speaker was referencing the slogan ISIS used at the height of its successes: "Remaining and expanding."

On Wednesday, General Frank McKenzie, head of U.S. Central Command, released declassified images and video from the raid that resulted in al-Baghdadi's death.

Abu Bakr al-Baghdadi is displayed on a monitor as U.S. Central Command Commander Marine Gen. Kenneth McKenzie speaks at a joint press briefing at the Pentagon in Washington, Wednesday, Oct. 30, 2019, on the Abu Bakr al-Baghdadi raid. Andrew Harnik / AP

U.S. Central Command (CENTCOM) shared video on Twitter that showed fighters near the compound beginning to fire on U.S. aircraft participating in the raid.

Al-Baghdadi's remains were "buried at sea in accordance with the Law of Armed conflict within 24 hours of his death," according to CENTCOM.