"ISIS has a new leader. We know exactly who he is!" Trump tweeted. US officials did not give any more details.

Islamic State earlier confirmed the death of its leader al-Baghdadi in a statement and named his replacement as Abu Ibrahim al-Hashimi al-Quraishi.

However, little is known about Hashimi, whose name was seldom mentioned as a possible successor the multiple times that Baghdadi was falsely reported killed in recent years.

Baghdadi, who led IS since 2014 and was the world's most wanted man, died in a US special forces raid in Syria's northwestern province of Idlib on Sunday.

Islamic State also confirmed the killing in another raid the following day of the group's previous spokesman, Abu Hassan al-Muhajir.

The statement said the jihadist group's legislative and consultative body convened after the 48-year-old Iraqi-born jihadist chief's death and "agreed" on a replacement.