Kata'ib Hezbollah is one of the Ira

Kata'ib Hezbollah is one of the Iranian-backed "Special Groups" of Shi'a militias that carried out attacks on coalition forces during the Iraq war. Since the U.S. withdrawal, the group has deployed fighters to Syria and has also set up a front group in Iraq, Saraya ad-Difa' ash-Sha'abi ("Popular Defense Brigades"), to assist Iraqi government forces to roll back Sunni insurgent advances, most notably in the Tikrit area, where security sources speaking to pro-government outlets readily admitted coordination. Kata'ib Hezbollah, as an Iranian proxy, espouses the Khomeinist ideology of Wilayat al-Faqih ("Guardianship of the Jurist"). Kata'ib Hezbollah has emerged as one of the most powerful militias in Iraq despite not having a formal political wing.

Though it had largely been focusing on the Iraqi home front since the outbreak of the Islamic State crisis in summer 2014, the group responded to a call from IRGC commander Qasim Suleimani to deploy units in Aleppo province to assist new offensives in the wake of the Russian intervention in Syria in support of the Assad regime in fall 2015.