Fierce fighting broke out in the city of Idlib and in southern and eastern parts of the province after Tahrir al-Sham detained a number of defectors who had together formed a new operations room, a local activist said.

The new operations room, known to its hardline members as "Fathbatu" (Hold Steadfast), comprises Hurras al-Deen, Ansar al-Islam, Ansar al-Deen, Tansiqiyat al-Jihad and Liwa al-Muqatilin al-Ansar.

The formation of the new bloc enraged Tahrir al-Sham, which issued a decree stipulating that would-be defectors are not to leave the alliance without permission, the Syrian Observatory for Human Rights said Tuesday (June 23rd).

Per the decree, Tahrir al-Sham elements and leaders who are granted permission to leave the group are then prohibited from forming new factions.

Following the formation of the Fathbatu operations room, Tahrir al-Sham went after Liwa al-Muqatilin al-Ansar leader Jamal Zainiya ("Abu Malik al-Talli"), Idlib activist Musab Assaf told Diyaruna.

Zainiya was detained by Tahrir al-Sham elements during a raid on his house in the town of Sarmada in eastern rural Idlib, Assaf said.

Tahrir al-Sham also detained Ansar al-Deen leader Siraj al-Din Mukhtarov ("Abu Salah al-Uzbeki"), who had fought in the ranks of Tahrir al-Sham and defected.

The detentions sparked fierce fighting, in which machine guns and missiles were used, between Tahrir al-Sham and the new Fathbatu bloc, Assaf said.

The "arrest warrants" were issued after a large number of fighters defected from Tahrir al-Sham and joined the rival groups and their newly formed operations room, Assaf said.

Rubbing salt into the wound, they took with them large sums of money, he said.

Tahrir al-Sham tried to recover these funds, particularly from Zainiya, who reportedly seized $20 million from the group's coffers, he said.

Fighting kicked off between the rival extremist alliances in the Idlib region amid mutual calls to mobilisation by the two sides that saw Tahrir al-Sham fighters deploy at several checkpoints, particularly at the entrances to towns, he said.

This indicates that Tahrir al-Sham has issued "wanted lists", Assaf said, noting that the extremist alliance has issued a decree in which it threatens to detain and imprison anyone who defects from it and joins these groups.