The "shadowy head'' of the Yarmouk Martyrs Brigade, a key ISIS militia, was killed in a recent suicide bombing north of Syria. Al Qaeda's Al Nusra Front has claimed responsibility for the attack.

Muhammad "Abu Ali'' al-Baridi, who went by the nickname of "The Uncle,'' was killed along with five other ISIS militiamen during a meeting on Nov. 15. The brigade is known for its bloody and vicious hold over parts of the Golan Heights, Fox News reported.

Al Nusra Front described the attack as "heroic.''

The suicide bombing that killed the ISIS leader came two days after the Paris attacks that killed 130 people.

Reports said Baridi's death was a stunning blow to the ISIS in Syria. "The Islamic State [ISIS], that controls the closest area to the Israel border in the Syrian Golan Heights, suffered a severe blow and lost its entire top command in the area in one fell swoop," said Alex Fishman, a veteran military correspondent for Israeli daily Yediot Aharonot.

"We heard the sound of a strong explosion coming from the former Baath Party headquarters in the village," Abu al-Ezzam, a resident in the Syrian town of Jamleh, told Syria Direct. "We ran to the place, and there were body parts scattered everywhere."

Al-Ezzam added that the village was "known as a meeting place for [the Yarmouk Martyrs Brigade] leadership."

The Lebanon Daily Star reported that Nusra Front has also called on ISIS fighters, who number about 2,000, to surrender.

In a defiant statement released on social media, the Yarmouk Martyrs Brigade reportedly responded: "The martyrdom of the leaders will only make us more determined. Blood and sacrifice is welcome for God's sake."

Regional experts believe that the successful suicide mission against such a significant affiliate shows a "degree of on-the-ground vulnerability on the part of ISIS," Fox News reported.

ISIS and Al Qaeda are known terrorist groups that have brought damage to lives and properties in the U.S. and elsewhere in the Middle East and some parts of the world. But the black-clad ISIS killers actually sprang from al-Qaeda and have largely captured the international spotlight with their mass executions, gruesome beheadings and even the apparent use of chemical weapons, said the report.

Despite the deadly attack that took out the Yarmouk Martyrs Brigade's leadership, Fishman said this will not mark an end to ISIS control of the Golan.

However, experts said al-Qaeda—the organisation behind the infamous 9/11, 7/7, and countless other major atrocities—is "not surrendering its long-time perch atop the terror heap."