When it comes to analysis of Iraq's Sunni insurgency, one of the most important questions is trying to determine which groups are in what area, particularly regions out of government control. One pattern that emerges is that the Islamic State (IS) comes to assert itself in the main urban area, and other factions, if they survive, end up fighting on the periphery of the city and/or disperse into nearby villages and countryside of the wider district.
To give an example, the city of Tikrit, which is now almost wholly depopulated, is under the control of IS, but there are other factions that play a defensive role against pro-govt forces on the surroundings and in nearby localities in Salah ad-Din province, including the Islamic Army in Iraq and the General Military Council for Iraq's Revolutionaries (GMC- more on this below and its relationship with the Jaysh Rijal al-Tariqa al-Naqshbandia [JRTN]- a Ba'athist oufit- below). Initially, multiple factions participated in the fall of the city of Tikrit, including IS' jihadi rivals Jamaat Ansar al-Islam, but IS very rapidly asserted its authority in the city at their expense. Yet here is a recent GMC report on fighting pro-govt forces on the southern periphery of Wadi Shishin just outside the urban area.
The city of Fallujah similarly fell to multiple factions in January, but IS has only gradually claimed a position of dominance through a mixture of co-optation and coercion, such that only a group under Sheikh Abdullah al-Janabi (Salafi: veteran of the Iraq War) is now left to share power with it, along with a military council of Saddam-era army officers. Outside the actual urban area, other factions that had otherwise been subjugated by IS within the city endure. Thus, note this recent report from the pro-insurgent outlet Quraish entitled "No Da3esh [IS] in al-Sijr...who is fighting there?":
"At the north-east entrance of Fallujah, continuous battles have been taking place for three days in an intense escalation...and this entrance is al-Sijr, which is under the control of the forces of the Military Council for the Revolutionaries of the Tribes [MCRT], including in them the forces of JRTN and Jaysh al-Mujahideen, and there are no members of Da3esh in these places."
MCRT is a term used for a number of local bodies in Sunni Arab provinces that were first announced via JRTN's activist wing Intifada Ahrar al-Iraq at the beginning of this year. It is also a term for local affiliates of the GMC, which itself reported on activity in the al-Sijr area recently on 16 September:
"The revolutionaries of Fallujah managed to seize complete control the al-Sijr area after confrontation with build-ups of the enemy army and its militias, leading to the destruction of a great number of vehicles and heavy losses of men. They also managed to seize a great number of vehicles, armored vehicles and tanks, as well as different sorts of weapons: heavy, medium and light..."
These reports thus point to the overlap between JRTN and the GMC at the local level (the Tikrit situation is similar), but we can also see how the GMC acts as a potential umbrella for other factions: this is particularly so for the 1920s Revolution Brigades that are linked to Harith al-Dhari, who also has clear ties with the GMC via his al-Rafidayn TV channel. Yet assuming the al-Quraish report is completely accurate, then the GMC is also acting as an umbrella in the SIjr area for the Salafi nationalist Jaysh al-Mujahideen, which originally had a presence within the city of Fallujah as well.
Update: Here's a video via Intifada Ahrar al-Iraq of JRTN operations in al-Sijr area.