The fatwa essentially aims to warn moderate rebel groups against abiding by the Russian, Iranian and Turkish-sponsored ceasefire agreement.
The statement released by Tahrir al-Sham, led by al-Qaeda's former arm in Syria, Jabhat Fateh al-sham, also known as the the Nusra Front, threatened to wage an unrelenting war on other Syrian rebel groups, such as the so-called Free Syrian Army, if those groups follow the terms of the agreements signed by Russia, Iran and Turkey recently.
The deal propounds the idea of dividing Syria into "de-escalation zones," areas in which fighting and bombing would be prohibited. Tahrir al-Sham dismissed the deal, arguing that it is a conspiracy theory by the powers against the Syrian revolution. Subsequently, the jihadi coalition argued it would begin launching attacks against any and all Syrian rebel groups that support the zones.
"Accepting the Astana agreement is a betrayal of god, his messenger and the believers, as it is the betrayal of the blood spilt in efforts attempting to liberate al-Sham [Syria] from the hands of the disbelievers," said the group in a statement.
"For this reason, abolishing groups that are attempting to thwart our Jihad is Jihad in itself. It is a duty upon every Muslim. This ruling includes those groups as well as their collaborators or those who allow them to work under their banner. All of these are bad and should be killed," the group added.
Tahrir al-Sham was born in February 2017 out of al-Qaeda's former affiliate in Syria, Jabhat Fateh al-Sham, as well as other groups, including the ultra-puritanical group, Ahrar al-sham. The coalition is concentrated in the city of Idlib in northwestern Syria, and its formation was seen by analysts as a way for the jihadi groups — with the exception of Daesh — to come together in order to dominate swathes of western Syria.
The Nusra Front has made rapid territorial acquisition since its establishment in 2011. By mid-2016, the group had vast territory in northern, western, and small pockets in southern Syria under its control, including most of the Idlib province.
Before it severed the ties with al-Qaeda, the Nusra Front had a long history of following the received diktat of Osama Bin Laden's successor, Ayman al-Zawahiri. However, in July 2016, Zawahiri released an audio statement in which he conceded that the Nusra Front's continued subservience to al-Qaeda Central was "conflicting with unity and working as one body." Following this, Nusra went its own way by declaring a formal divorce from al-Qaeda. Some analysts suggested that the separation from al-Qaeda was an attempt for the group to refashion itself in a more moderate suit, in the hope that this could attract more largesse from Gulf state financiers sympathetic to the jihad being waged in Syria.
The Nusra Front and its tacit allies, such as Ahrar al-Sham, adhere to a Salafist-jihadist ideology which has the aim of establishing a Caliphate — or Islamic state — in areas under its sway.
Back in 2012, the group released a video introducing itself to the Syrian maelstrom. In the video, a Nusra ideologue outlined the group's primary objectives. He spoke of jihadists coming to Syria to "restore god's rule" and to "avenge the Syrians' violated honor and spilled blood." Years later, when the group's leader, Abu Muhammad al-Julani, announced Nusra's separation from al-Qaeda, he exclaimed that this was not "compromising or sacrificing our [Nusra's] solid beliefs or laxity in the necessity of the continuity of the Jihadi."
It would however, be a mistake to assume that Syria is the Nusra Front's exclusive sphere of operation. It also has cells in Lebanon, and stands accused of sponsoring some of the attacks seen in Europe since the Syrian civil war broke out in March 2011.
It is very likely that Nusra and its Tahrir al-Sham coalition see the establishment of the de-escalation zones in Syria as a direct threat to the contiguity of the territory they control.
It must be considered that the opposition groups on the ground in Syria, many of which receive largesse from overseas patrons, will be steered toward supporting the Astana outcome to avoid risking the continuity of their weapons supplies.
Regional states, namely Turkey, have been frantically trying to forge a new umbrella group of moderate Syrian rebels to repel the tumorous Tahrir al-Sham coalition. However, not only is this effort moving slowly on the ground in Syria, it has also garnered little support for the US, who says that it only condones supporting factions that it has vetted.
Turkey can expect little sympathy from Washington after President Erdogan condemned the Trump administration's decision to continue arming the Kurdish YPG in Syria.
President Erdogan said that any US failure to take into account Turkey's concerns over Kurdish groups in Syria will, "surely have consequences and will yield a negative result for the US as well." He also said that "we want to believe that our allies will prefer to side with us, not with a terrorist organization."