Diyala campaign

The Diyala campaign was a series of operations conducted by coalition forces against Iraqi insurgents and a number of bombing and guerrilla attacks against the security forces in the Diyala Governorate of Iraq, with the purpose of control of the province and reducing insurgent activity.

In mid-October 2006, al-Qaeda announced the creation of the Islamic State of Iraq (ISI), replacing the Mujahideen Shura Council (MSC) and its al-Qaeda in Iraq (AQI).

In 2006, Diyala province had special significance for the insurgents.^{[clarification needed]} When Abu Musab al-Zarqawi was head of al-Qaeda in Iraq, he designated Diyala as the capital of the Islamic caliphate he planned to establish in the country. He located his headquarters in a village north-west of Baqubah. On 28 April 2006, on Saddam Hussein's birthday, insurgents of the Mujahideen Shura Council including al-Qaeda in Iraq launched a coordinated offensive throughout the province, attacking Muqdadiyah, Balad Ruz, Kanaan, Khalis, Khan Bani Sa'ad and the capital Baqubah. The insurgents used the rural areas east and southeast of the capital, from Balad Ruz to Turki as supply bases for their bombing campaigns in Baghdad and Diyala. They were also based in the Diyala river valley, northeast of Baqubah, where they fought for control of Muqdadiyah, an important line of communication to Lake Hamrin, Kirkuk and Iran. The insurgents also had control of the tribal areas of Khan Bani Sa'ad south of Baqubah to Salman Pak, south-east of Baghdad.

Shortly after the insurgent victory in Baghdad after Operation Together Forward insurgents began, little by little, moving their resources from Baghdad, now more than 80 percent under insurgent control, and Al Anbar province, which was also almost completely under insurgent control, to the province of Diyala northeast of Baghdad. The first signs of increased insurgent activity in Diyala came after U.S. forces found an insurgent bunker complex near the village of Turki and fought a bloody battle. Also a few weeks later fighting between police and insurgents after an attack on Baquba's police headquarters shut down the city, closing the university, schools and most stores, and clearing the streets of everyone, except a few who attempted to stock up on food. At least 55 militants were killed in clashes in the preceding days, according to anonymous police sources. During the fighting a mass grave with 28 bodies was discovered. After that U.S. and Iraqi forces begin raids in the city. The morgue in the city reports by the beginning of December 2006 that it had received 102 bodies in the previous two weeks. After the announcement of a new attempt by the U.S. and Iraqi security forces to take back the streets of Baghdad the insurgents started to speed up their move and it is believed that the reason behind the little resistance found by the security forces in Baghdad during Operation Law and Order is that most of the insurgents had moved to Diyala.

On Christmas Day, it was reported that the capital of the province, Baquba, had fallen under insurgent control. An Iraqi news cameraman went to the city and reported seeing hundreds of gunmen with AK-47s in cars and pickups parading through the city. There was no sign of the security forces except for the bodies of a few executed by the insurgents. After that, there were increased insurgent attacks on the U.S. and Iraqi forces around Baquba and in the rest of the province.

In mid-January, U.S. and Iraqi forces conducted a series of raids that resulted in 93 insurgents killed and 57 captured. Despite that, however, the insurgents had some successes early in the campaign, mainly when they shot down a Black Hawk helicopter on January 20, killing twelve U.S. soldiers. The helicopter was carrying mostly officers from the U.S. National Guard. The dead included a colonel who was the top American military doctor in Iraq.

In January 2007, it was reported that Sunni militants were able to kidnap the mayor of Baquba and blow up his office, despite promises from American and Iraqi military officials that the situation in the city was "reassuring and under control". The city at its peak had over 300,000 residents, but a February 2007 report labeled the city a "ghost town" as most residents had fled.

In two separate incidents in the beginning of March, insurgents captured 32 members of the Iraqi security forces. The bodies of 14 captured policemen were found shortly after, and the 18 other soldiers and policemen were shown on television with a message that they would be executed. Suicide bombers continued to attack in Diyala, targeting not only military but also civilian targets such as a cafe in Balad Ruz, where 30 people were killed on March 7. The capture of policemen continued, with another 10 policemen captured and 1 killed when insurgents overran a police station in the town of Hibhib. The bodies of five of the policemen were found the next month. Also, 20 Iraqi soldiers and policemen were captured at the beginning of April and were executed several days later.