After being released, Zainuri left Malaysia in April 2014 and travelled to Syria to fight in the local civil war;[2][5] he left his second wife, Rahimah's sister, behind.[4] In Syria, Zainuri initially joined Ajnad al-Sham,[9] but soon switched allegiance to the Islamic State of Iraq and the Levant. In August 2014, he and another former KMM member, Zainan Harith, were ambushed by the Syrian Army; Zainan was killed, while Zainuri was wounded at the neck and thigh.[5][2] At some point, he became one of the commanders of the Malay-speaking ISIL frontline unit Katibah Nusantara.[5][8] In this position, Zainuri recruited new members for ISIL through Facebook,[5] trained child soldiers for Katibah Nusantara,[8] and issued orders to ISIL cells in Malaysia.[10] Due to his activities and his status as "rather influential personality" among ISIL supporters, he was closely monitored by the Royal Malaysia Police.[1][8]