Badr Organisation: Seen as the most militarily capable faction in the Hashd. Iraqi Shiite exiles opposed to Saddam Hussein set up the group in Tehran in the early 1980s as the Badr Corps under the supervision of the Iran Revolutionary Guards Corps (IRGC). The militia exalts Iran’s Supreme Leader Ali Khamenei but intermittently cooperated with the US military.
Saraya Al Salam (Peace Brigade): Comprised of former members of the officially defunct Mahdi Army, a militia that was commanded by Iraqi cleric Moqtada Al Sadr and fought US and Iraqi government and other forces between 2004 and 2008. As part of a political overhaul aimed as casting Mr Al Sadr as a more nationalist and less sectarian figure, the cleric formed Saraya Al Salam in 2014. The group’s relations with Iran has been volatile.
Kataeb Hezbollah: The group, which is fighting on behalf of the Bashar Al Assad government in Syria, traces its origins to attacks on US forces in Iraq in 2004 and adopts a tough stance against Washington, calling the United States “the enemy of humanity”.
Asaeb Ahl Al Haq: An offshoot of the Mahdi Army active in Syria. Asaeb Ahl Al Haq’s leader Qais al Khazali was a student of Mr Al Moqtada’s late father Mohammed Sadeq Al Sadr, a prominent Shiite cleric who was killed during Saddam Hussein’s rule.
Harakat Hezbollah Al Nujaba: Formed in 2013 to fight alongside Mr Al Assad’s loyalists in Syria before joining the Hashd. The group is seen as among the most ideological and sectarian-driven Hashd militias in Syria and is the major recruiter of foreign fighters to Syria.
Saraya Al Khorasani: The ICRG formed Saraya Al Khorasani in the mid-1990s and the group is seen as the most ideologically attached to Iran among Tehran’s satellites in Iraq.
(Source: The Wilson Centre, the International Centre for the Study of Radicalisation)