By Emily Anagnostos and the ISW Iraq Team
ISIS launched waves of counteroffensives and spectacular attacks across Iraq after operations in eastern Mosul resumed on December 29. The attacks were widespread and hit highly secured areas, including Baghdad and the shrine cities of Najaf and Samarra. ISIS also attempted to sever the main highway running from Mosul to Baghdad by attacking locations north of Baiji. The attack pattern is similar to ISIS’s attacks in the week after the Mosul operation launched on October 17, when ISIS struck targets in Kirkuk, Sinjar, Rutba, and Samarra, and in the week after the Iraqi Security Forces (ISF) breached Mosul’s city limits on November 1, when ISIS launched major attacks in Tikrit, al-Alam, Samarra, and Shirqat. The most recent attacks from December 29 to January 5 underscore that ISIS will react to major phase changes in Mosul by launching wide-spread attacks with the intent to spread the ISF thin, force it to reallocate units away from northern operations, and undermine political legitimacy in Baghdad. The attacks demonstrate that, despite its losses in Mosul, ISIS is capable of reopening old fronts, such as in Sinjar which it lost in November 2015; penetrating deep behind the frontlines, such as Kirkuk City; and retaining access into highly secured areas, such as Baghdad and Samarra. Continued minor attacks in the Euphrates River Valley also suggest that ISIS may be reviving networks in historical support zones. The ISF and Coalition can reasonably expect that ISIS will launch a similar wave of attacks across Iraq when the ISF reaches and crosses the Tigris River in Mosul.