The differences started among the ISIS leaders after the appointment of a new commander for Deir Ezzor.
The ISIS appointed Yousef Marhoun al-Wahibi as the commander of its Syrian militants in Deir Ezzor city and its countryside.
Al-Wahibi replaced his niece Saddam al-Jamal who was killed last March in al-Mayadeen city in the Syrian army attack.
Al-Wahibi played an important role in ISIS late March attack on Al-Assad Hospital where the hospital's medical staff members were massacred.
On Monday, the Syrian Army, Air Force and artillery units targeted ISIS concentration centers in different parts of the Eastern province of Deir Ezzor, pinning the militants down behind their defense lines.
The Syrian fighter jets bombed ISIS base in Western side of Deir Ezzor airbase, which claimed the lives of several militants.
The Syrian army troops, for their part, stormed ISIS centers in al-Tharda mountain and Huweija al-Saker.
The Syrian army's artillery units opened heavy fire at ISIS positions in Panorama square, which killed most of a 10-member ISIS group.
In relevant development on Saturday, the Syrian Air Force, in several combat flights, targeted ISIS positions and bases in different parts of the Eastern province of Deir Ezzor, destroying their military hardware and their bases' infrastructures.
One of the headquarters of the ISIS in Southern side of the village of Albu Leil near Deir Ezzor city was completely destroyed and the entire members of the ISIS in the headquarter were killed in the Syrian warplanes' attacks.
In the meantime, the Syrian fighter jets pounded ISIS bases in Ein Albu in Western side of Deir Ezzor city, which ended in the explosion of an ammunition depot and a bomb-laden car, FNA reported.
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