Rebel fighters make improvised mortar shells inside a weapons factory in the southern countryside of Idlib September 9, 2014. Picture taken September 9, 2014. Image Credit: Reuters

Beirut: An ultraconservative Syrian rebel group named a new leader and military chief on Wednesday, less than 24 hours after an explosion killed nearly a dozen of its senior figures in a potentially fatal blow to one of the most powerful factions in the country’s armed opposition.

The group, Ahrar Al Sham, has been among the steadiest and most effective groups fighting to oust President Bashar Assad in Syria’s civil war, now in its fourth year. It has also been on the front lines of a now nine-month battle in northern Syria against the extremist Islamic State of Iraq and the Levant (Isil). Ahrar Al Sham had blamed Isil for the killing of one of their leaders in February, a man known as Abu Khalid Al Souri, a confident of former Al Qaida leader Osama Bin Laden.

Ahrar Al Sham fused its ultraconservative religious views with an often more practical political position, allowing it to act as a bridge of sorts between the more moderate Western-backed groups and radical factions, such as the Al Qaida-linked Al Nusra Front. The question now is whether the group can survive the loss of nearly all of its senior leaders.

The blast late Tuesday struck a high-level meeting in the town of Ram Hamdan in Idlib province in northwestern Syria. Ahrar Al Sham’s top boss, Hassan Aboud, was among the dead.

On Wednesday, a spokesman for the group said in a video statement posted online that Hashem Al Shaikh Abu Jaber would assume overall leadership, while Abu Saleh Tahan would fill the role of military commander. The attack struck a high-level meeting of Ahrar Al Sham, or The Islamic Movement of Free Men of the Levant in English, held in the northwestern town of Ram Hamdan in the Syrian province of Idlib, one of its strongholds. A statement from the group said the blast killed Aboud, also known by the nom de guerre Abu Abdullah Al Hamwi, along with 11 other top leaders.

“They were martyred ... in an explosion inside their meeting headquarters,” said a statement on the Twitter feed of the Islamic Front, the rebel coalition to which it belonged.

The Idlib News Network said over 40 people were killed in the blast. .

While Ahrar Al Sham was an ultra-conservative group, its leadership, including Aboud, sought to balance “the group’s fundamentalist platform with a relatively pragmatic political strategy”, said Noah Bonsey, a Syria analyst for the International Crisis Group. Aboud had even once met with a top US State Department official, Bonsey said.

“Ahar Al Sham had been one of the best led and most organised and, overall, one of the most effective groups on the ground,” Bonsey said. “It’s a loss of talent within the rebel spectrum as a whole. Ahrar Al Sham was one of the strongest, if not the strongest rebel group, and the question is, what will it look like going forward?”

Syria’s conflict began as large demonstrations against Al Assad’s rule that collapsed into a war with sectarian undertones. Rebels are overwhelmingly from Syria’s Sunni majority. Many in Syria’s minority groups have backed Al Assad or remained neutral, fearing for their fate should rebels come to power.

The conflict has been further complicated by militants of the Islamic State group, whose mass killings, beheadings and targeting of minority groups has sparked international outrage. US President Obama is now trying to gather an international coalition to challenge the group.