The Fight Continues – Phase II. After a two-week lull in the action in the waning days of December the Iraqi military and its allies (Kurdish Peshmerga, Iran proxy militias, etc.) have re-started the campaign to re-capture Mosul. Phase II kicked off on December 29th. Almost 1/3 of Mosul has already been taken but the Islamic State is putting up a determined defense of their remaining holdings. The first phase of the operation started in mid-October.
Counter Terrorism Service (CTS). The Iraqi special forces have been in the lead for the retaking of Iraqi’s second largest city but have suffered some significant losses. ISOF is being assisted by the 9th and 16th Divisions of the Iraq security forces. Militarized units of the Federal Police are also functioning as ‘hold forces’ in areas that have been ‘liberated’ by the military. The CTS is being reinforced with more personnel to ensure it is combat-ready once again. The level of training that these replacements possess is subject to question.
Militia Groups. The Iranian proxies – most of them part of the Popular Mobilization Forces (PMF) – are for the most part, Shiite militia groups. There are a few PMF elements that are Sunni. There are also some unofficial militia groups (not part of the PMF). A few of these come from the Mosul region (Knights of Ninewa) and others from other regions of Iraq. Many of these unofficial militias are a composite of Arab Shiites, Sunnis, Yazidis, and Christians.  For now, the militia groups are being used on the outskirts of Mosul – fears of a backlash against the Shia militias are contributing to the governments decision to keep the militias out of the city. That . . . and the reputation of the militias in previous actions against Sunni population centers has kept them sidelined as well.
Peshmerga in Defensive Posture. The Kurds are also staying out of the city proper. They are now busy solidifying gains made against ISIS in the surrounding areas. Once again, the Iraqi government is concerned about Kurds advancing into the city during Phase II – worried on the likelihood that they could decide to keep what they gain.
Up to the CTS. This means the taking of Mosul during phase II is squarely on the shoulders of the Counter Terrorism Service. The CTS is not a urban fighting force. It isn’t trained for that mission – it is trained to conduct special operations. Military Operations in Urban Terrain (MOUT) is a conventional force mission. Unfortunately the Iraqi army isn’t up to the task so the CTS will be pressed into service once again.
Civilians at risk. There is an estimated one million civilians (perhaps more) still left in Mosul. Many thousands have been able to leave the city – desperate to find safety, food, and water. The densely packed civilian areas of Mosul preclude the level of air support that the U.S. and other Coalition nations were able to offer the CTS when it took Ramadi and Fallujah in 2016.
U.S. Forces. There is a big mix of United States military forces in the country. This includes special operations, medical, artillery, Army aviation, U.S. Air Force and training teams. According to the Pentagon there are about 5,000 U.S. troops in the country; although, the number is a few thousand higher if you count the folks there on temporary duty that flow in and out.  A decision was made to embed more U.S. advisors at lower levels within the Iraqi military during Phase II of the Mosul offensive – partnering with forces that had (up to this point) not seen Americans with their formations. 
Other Countries as Well. The United States is not in this alone. There are a host of other countries participating in the effort against the Islamic State. Some have offered air support (Britain, France, etc.), some have deployed special operations forces (Canada, Australia, etc.), and these countries have suffered personnel losses as well. 
Plan of Attack for Phase II? The plan to take Mosul is with an attack along three axes. The Iraqi army’s 16th Division is coming in from the north and advancing south. The Counter Terrorism Service is pushing west and south along two fronts (from its positions in the east), and on the southern edges of the city the Federal Police (the Federal Police are augmented by the MoI’s Emergency Response Division ) are clearing neighborhoods in a northerly direction.  The PMF (mostly Shia militia) hold the western edges of the city but have been restrained by the Iraqi government from proceeding further.
Timeline and Aftermath? Ultimately the city of Mosul will fall to the Iraqi government forces. The toll on the Counter Terrorism Service will be significant – and could render it combat ineffective for quite a while. This will deprive the Iraqi government of a loyal and highly trained counter terrorism and special operations force. Other units and militias will fill the security void – and there is the big concern.
 “The Many Armies of Iraq: If ISIS Goes, Do They Turn on Each Other?”, by Kimberly Dozier, The Daily Beast, January 2, 2017.
 “US General Praises Iraqi Forces Fighting in Mosul“, The New York Times, January 1, 2017.
 See “U.S. forces embedding more to help Iraqis retake Mosul”, Reuters, December 24, 2016.
 The United Kingdom just lost a soldier from the 2nd Battalion of the Duke of Lancaster’s Regiment in early January. See “Ministry of Defence confirms death of British soldier in Iraq”, International Business Times, January 2, 2017.
 The Emergency Response Division of the MoI had it’s start in late 2003 / early 2004 as the Emergency Response Unit (ERU). At that time the ERU was a small but highly effective 30-man Iraqi police unit funded by the U.S. State Department and advised by two contract Americans who were reservists with (now deactivated) 12th Special Forces Group.
 For info on axes of attack see “Iraqi Forces Resume Mosul Offensive”, U.S. Central Command News Release, December 29, 2016.