This is the same strategy they used in 2006 when Abu Musab al-Zarqawi was the group’s emir, the main difference now is they will be fighting the hapless Iraqi army instead of the U.S. military.
Via Long War Journal:
The lightning advance of the Islamic State of Iraq and the Sham and its allies from Mosul to the outskirts of Samarra, as well as its capture of several towns in eastern Diyala, all over the course of several days, appears to be part of a greater strategy to surround the capital of Baghdad before laying siege to it. This plan, to take over the “belt” region outside of Baghdad and cut off the capital, appears to be the same strategy used by the ISIS’ predecessor back in 2006.
The 2006 plan, which was drawn up by the Islamic State of Iraq (ISI), the forerunner of the Islamic State of Iraq and the Sham (ISIS), was discovered after the US found a crude map on the body of Abu Musab al Zarqawi, al Qaeda in Iraq’s leader who was killed by US forces in Baqubah in June 2006. The “Baghdad belts” map was released by Multinational Forces-Iraq during its offensive to liberate vast areas under al Qaeda/ISI control in 2007 and 2008.
Zarqawi’s plan was to seize control of the outer provinces and Baghdad’s belts, or key areas surrounding the capital. The ISI would then use its bases in the belts to control access to Baghdad and funnel money, weapons, car bombs, and fighters into the city. The ISI also planned to strangle the US helicopter air lanes by emplacing anti-aircraft cells along known routes in the belts areas around Baghdad.
In the ISI’s 2006 plan, the Baghdad belts were divided into five regions: the “Southern Belt,” which included northern Babil and southern Diyala provinces; the “Western belt,” which included eastern Anbar province and the Thar Thar area; the “Northern belt,” which included southern Salahaddin province and cities such as Taji; the “Diyala belt,” which included Baqubah and Khalis; and the “Eastern belt,” which included the rural areas east of Baghdad.
Watching the ISIS’ operations today, it appears the group is attempting to implement a strategy which is very similar, if not identical, to the previous one. This should come as no surprise; Nasser al Din Allah Abu Suleiman, ISIS’ current war minister, was a leader in al Qaeda in Iraq/ISI when the Baghdad belt strategy was implemented. Suleiman was appointed by al Qaeda in May 2010 to serve as the terror group’s top military commander after his predecessor, Abu Ayyub al Masri, was killed in a raid by Iraqi and US forces in April 2010.