A former commander of the Iraqi ground forces, Ali Ghaidan, accused former Prime Minister of Iraq, Nuri al-Maliki of being the one who issued the order to withdraw from the city of Mosul.

However, despite the security crisis, Iraq's parliament did not allow Maliki to declare a state of emergency; many Sunni Arab and Kurdish legislators boycotted the session because they opposed expanding the prime minister's powers.

Anne-Marie Slaughter wrote that had Obama forcibly intervened in the Syrian civil war, it "could have stopped the carnage spreading today in Syria and in Iraq,"[56] while Fareed Zakaria, editor of Time and former Middle Eastern policy advisor for the Bush administration,[clarification needed] alleged that counterproductive western intervention in Iraq and Syria served to accelerate sectarian infighting in both countries and empowered radicals on all sides.

[65] Washington Institute for Near East Policy analyst Michael Knights noted that mutual opposition to the Shia-led government allowed for an alliance between the hitherto ideologically opposed ISIL and secular Ba'ath influenced insurgents such as the Naqshbandi order.

The ISIL operatives blew up a police station south of Samara overnight, killing several policemen, before they advanced on the city in pick-up trucks, raiding checkpoints along the way.

[77] At the same time, ISIL advanced to the east of Mosul, capturing the Hawija, Al Zab, Riyadh, and Abbasi areas west of the city of Kirkuk, and Rashad and Yankaja to its south after government forces retreated.

Ghaidan and Qanbar's retreating convoy created the impression that Iraq's security forces were deserting[73] and so Iraqi Army soldiers started to flee Mosul.

[90] There were conflicting reports about the east bank of Mosul, which has a significant population of Assyrians, Kurds, Turkmens, Shabaks and Armenians,[91] with some suggesting it was controlled by Kurdish Peshmergas[92] while according to others it was ISIL-controlled.

[93] Sources within the Iraq government allege that in the months preceding the assault, Ba'ath loyalists led by al-Douri had been in contact with disaffected Sunni officers who either defected or withdrew upon the ISIL-Ba'ath attack.

[43] Continuing their offensive, on the evening of 11 June, insurgents took full control of the city of Tikrit, the hometown of former president Saddam Hussein and the second provincial capital to fall in two days.

[22] Journalists from Al-Monitor embedded in Mosul and Tikrit reported that repeated airstrikes by the government made ISIL militants depart from conspicuous positions within the cities.

[111] According to The Guardian newspaper, the call to arms by the highest Shia authority in Iraq, Grand Ayatollah Ali Sistani, on 13 June mobilized in less than one day around a division of militiamen who, unlike the military, would not run from a fight with the insurgents.

[138] At the same time, Rauf Rashid Abd al-Rahman, the presiding judge during the trial of Saddam Hussein, was reportedly captured and executed by insurgents,[139] though that was later denied by family members and the Kurdistan Regional Government.

[140] On 19 June, government forces claimed to have regained full control of the Baiji oil refinery, after heavy fighting with ISIL fighters that left 100 militants dead.

[141] An Iraqi witness who drove past the Baiji refinery told the Associated Press that ISIL had hung their banners from the watch towers and created checkpoints surrounding the facility, despite government claims of control.

[143] The same day, ISIL captured the Al Muthanna Chemical Weapons Facility near Lake Tharthar, 45 miles northwest of Baghdad, in an area which was firmly come under rebel control by this point.

[152] 400 soldiers of the 37th Brigade, including its officers, deserted from the refinery following an agreement reached with tribal leaders per which the troops had free passage to leave for 24 hours.

This left the insurgents in control of virtually the entire facility, except one compound where the refinery's operating systems are located due to the SWAT members barricading themselves in the building.

Instead, ISIL decided to slowly starve out the commandos if they refused to surrender, since no reinforcements could be flown in to the SWAT unit due to the heavy insurgent anti-aircraft fire around the refinery.

[153][154] By this point, sources reported that a combination of desertions, casualties and loss of equipment crippled the regular Iraqi military, forcing the government to increasingly rely on volunteers drawn from Shia militias.

[6] On 25 June, anonymous American officials reported that Iran set up a special control centre at Al-Rasheed Air Base in Baghdad and was flying a "small fleet" of Ababil drones over Iraq, and an Iranian signals intelligence unit had also been deployed at the airfield to intercept electronic communications between ISIL fighters and commanders.

[166] On 4 July, the ISIL published a video claiming its leader, Abu Bakr al-Baghdadi, delivered a sermon for half an hour during Friday prayers at the Great Mosque of al-Nuri Mosul, Iraq.

NBC quoted an unnamed senior U.S. counterterrorism official claiming that "the tribal groups do not necessarily follow strict Islamic law the way ISIS does, which naturally leads to conflict".

"Qaraqosh, Tal Kayf, Bartella and Karamlesh have been emptied of their original population and are now under the control of militants", Joseph Thomas, the Arch Bishop of the Iraqi cities of Kirkuk and Sulaimaniyah, told AFP.

Around Sinjar, the Peshmerga withdrew from the area without effectively communicating this development to the Yazidi inhabitants,[179] prompting the locals to flee to the Kurdistan Region after brief clashes with ISIS.

[181] Despite the security crisis, Iraq's Parliament was not convened and did not allow Maliki to declare a state of emergency; many Sunni and Kurdish legislators boycotted the session because they opposed expanding the prime minister's powers.

According to one of his representatives, Sheikh Abdulmehdi al-Karbalai, he asked for "people who are capable of carrying arms and fighting the terrorists in defense of their country... (to) volunteer to join the security forces to achieve this sacred goal".

The former officer claimed that the various opposition factions were working to minimize ISIL influence and appoint officials capable of restoring services in insurgent held areas.

[228][229] According to the Jerusalem Center for Public Affairs, "The Kurds, seeing the Iraqi central regime's weakness, will take all the necessary measures to protect their autonomy and expand their influence to neighboring Syrian Kurdistan.

"[230] Tirana Hassan, of the Human Rights Watch, reports that Khorasani Brigade, a Shia militia, has ethnically cleansed the village of Yengija, 50 miles south of Kirkuk.