DHAKA: The leader of one of Syria's most powerful rebel groups has been killed along with dozens of other commanders in a bomb attack on a high-level meeting in Idlib province.

Hassan Abboud, the head of the Ahrar al-Sham brigade, was among up to 45 people killed on Tuesday at the meeting in an underground bunker near an ammunition dump outside Ram Hamdan, reports Al-jazeera.

The Idlib meeting brought together Ahrar and a number of other brigades fighting as the Islamic Front alliance, such as Ahrar, Abdallah Azzam and the Iman brigades, to discuss a strategy to fight the Islamic State.

Activists named others killed in the attack: Abu Yazan al-Shami, a member of the Ahrar's shura council, military field commanders Abu Talha al-Askari and Abu Yousuf Binnish, and Abu al-Zubeir, the head of the Iman brigade.

Abu al-Mustafa al-Ambsi, a member of the political bureau of Ahrar, told Al Jazeera that the group was investigating the attack.

"There is a possibility that the meeting was infiltrated and an explosion happened first in the bunker," he said. "Maybe someone planted a device inside because the bunker is at a secret location”. 

He said that killing of such an elite group "will only make us more resilient to fight and continue the fight until we liberate our homeland". 

It is not known who staged the attack but Islamic State sympathisers hailed the death of Abboud on social media.

Another of Ahrar's leaders, Abu Khaled al-Souri, a close associate with al-Qaeda leaders Osama bin Laden and Ayman al-Zawahiri, was killed by the Islamic State earlier this year.

BDST: 1104 HRS, SEP 10, 2014