Daesh confirmed Thursday the death of its leader Abu Bakr al-Baghdadi and named Abu Ibrahim al-Hashimi al-Quraishi as his replacement.
In an audio statement, the terrorist group's new spokesman Abu Hamza al-Quraishi said, "We mourn you... commander of the faithful."
The group also confirmed the killing in another raid the following day of the group's previous spokesman Abu Hassan al-Muhajir.
The Daesh spokesman also issued a stark warning to the United States, whose President Donald Trump announced al-Baghdadi's death in a televised address from the White House.
"He died after running into a dead-end tunnel, whimpering and crying and screaming all the way," Trump said on Sunday, adding that Baghdad "died like a dog".
In the new audio message, the Daesh spokesman described Trump as "a crazy old man" and warned the U.S. its supporters would avenge al-Baghdadi's death.
Al-Baghdadi was killed in a U.S. military operation in Syria, officials announced on Oct. 27.
Under his leadership, the terrorist group took control of large swathes of land in Iraq and Syria and carried out deadly attacks inside both countries and abroad.
Al-Baghdadi had been a top target for both the Trump and Obama administrations and had a $25 million bounty on his head.