New ISIS leader Nasser al-Qirdash has reportedly been arrested in Iraq by security forces.
Nasser al-Qirdash was said to be the most favoured candidate to succeed former ISIS leader Abu Bakr al-Baghdadi.
al-Baghdadi was killed in a U.S. military operation in October last year.
He is said to have fled into a tunnel before setting off an explosive vest, killing himself and three of his young children in Syria.
A US AC 130 “flying gun” and Reaper drone armed with 500lb bombs then flattened the den after the troops had withdrawn.
Nasser al-Qirdash was the leading candidate to succeed Abu Bakr al-Baghdadi, according to reports.
Others at the compound surrendered, were shot or killed.
Trump said he got to "watch much" of the mission unfold and compared it to a movie.
He also revealed highly-sensitive material and information about ISIS, including its future plans, had been removed from the compound.
"The thug who tried so hard to intimidate others spent his last moments in utter fear, panic and dread, terrified of the American forces bearing down on him," said the president.
"He reached the end of the tunnel as our dogs chased him down. He ignited his vest, killing himself and his three children. His body was mutilated by the blasts. The tunnel had caved on him.
A brutal killer, one who has caused so much hardship and death, has violently been eliminated. He will never again harm another innocent man, woman or child."
Two of Baghdadi's wives, who were wearing suicide vests, were among the dead, he added.
Trump earlier posted a cryptic tweet which said: "Something very big has just happened!"
Islamic State leader Baghdadi, described as "one of the most evil men in history", had spent years in hiding after a $25million bounty was placed on his head.
The hate-filled 47-year-old inspired atrocities and spread poisonous messages encouraging violence, such as the Manchester Arena bombing.
