Two branches of the Islamic State (IS) have pledged allegiance to the group's new leader, Abu Ibrahim al-Hashimi al-Qurashi, who recently announced his choice and allegiance to his leader after the death of former leader Abu Bakr al-Baghdadi.

The Sinai Province, the Islamic State's branch in Egypt, and its branch in Bangladesh announced on Saturday loyalty to new leader Abu Ibrahim al-Hashimi al-Qurashi in the first sign of support from the organization's international branches.

The Sinai province published pictures of about 24 fighters in the trees, and wrote under the pictures "side of the allegiance of soldiers of the caliphate to the faithful Sheikh Mujahid Abu Ibrahim al-Hashemi al-Qurashi."

Al-Qurashi was declared leader of the organization in a voice message during which he also confirmed the killing of al-Baghdadi and vowed revenge against the United States; Baghdadi was killed after a raid by US special forces in northwestern Syria.

ISIS has been waging a guerrilla war since losing control of Syria's last major stronghold in March and has claimed responsibility for dozens of attacks in several countries around the world.