Beirut, Asharq Al-Awsat—Syria’s top Sunni cleric, Sheikh Mohammad Said Ramadan Al-Buti, was killed last night in a suicide bomb attack at the Iman Mosque in Damascus, along with at least 42 others.

Buti was a close political ally of under-fire Syrian President Bashar Al-Assad and had been one of the few remaining pillars of support for the Damascus regime among Syria’s Sunni majority. His death further weakens the ailing Assad regime.

In a rare statement issued via the state-run Syrian Arab News Agency (SANA) in the wake of the attack, Assad pledged to “purge” Syria of Muslim extremists. He stressed that “the blood of all today’s martyrs and all martyrs of the homeland will not go in vain.” “We are fighting to eliminate their obscurantist and takfiri thinking until we purge our country of them”, he added.

Syrian National Coalition leader Moaz Alkhatib also denounced the attack, stressing that the coalition’s member groups “categorically condemn the assassination.”

The attack highlighted the escalating disinformation war currently playing out between the Assad regime and the Syrian rebels, with the Syrian National Coalition not only condemning the attack but blaming the Assad regime for it. The coalition issued a statement claiming that “the terrorist Assad regime is directly responsible for this heinous incident.”

The statement added: “The Syrian National Coalition condemns without any hesitation, with the strongest expressions, the terrorist bombings’ method that the Assad’s regime excelled in implementing to reach its filthy objectives.”

The Free Syrian Army (FSA) has also denied responsibility for the attack. FSA spokesman Luay Al-Miqdad emphasized: “We do not do these types of suicide bombings and we do not target mosques.”

Earlier this week, Damascus and the Syrian rebels traded accusations over the use of chemical weapons in Aleppo. The Assad regime alleged that “terrorists” had fired a rocket “containing chemical weapons”, killing 16 people, while the rebels claimed that Assad forces were responsible for the attack. The UN is in the process of investigating this incident.

Buti is the most senior religious figure to have been killed in the conflict between the Assad regime and the Syrian rebels which has raged across Syria over the past two years. His death will come as a major setback for the government, which relies on an ever-decreasing number of supporters, especially with regards to Syria’s Sunni majority.

Earlier this month, Sheikh Buti had issued a speech asserting that it was a “religious duty to protect the values, the land, and the nation,” and that “there is no difference between the [Syrian] army and the rest of the nation.”