in which scores of people were killed when a truck bomb exploded near a Sunni mosque in Fallujah. Al-Qaeda supposedly played a role in the assassination of the leader of the Anbar-based insurgent group 1920 Revolution Brigade, the military wing of the Islamic Resistance Movement. In April 2007, the IAI spokesman accused the ISI of killing at least 30 members of the IAI, as well as members of the Jamaat Ansar al-Sunna and Mujahideen Army insurgent groups, and called on Osama bin Laden to intervene personally to rein in Al-Qaeda in Iraq. The following month, the government announced that AQI leader al-Masri had been killed by ASC fighters. Four days later, AQI released an audio tape in which a man claiming to be al-Masri warned Sunnis not to take part in the political process; he also said that reports of internal fighting between Sunni militia groups were "lies and fabrications". Later in May, the US forces announced the release of dozens of Iraqis who were tortured by AQI as a part of the group's intimidation campaign.
By June 2007, the growing hostility between foreign-influenced jihadists and Sunni nationalists had led to open gun battles between the groups in Baghdad. The Islamic Army soon reached a ceasefire agreement with AQI, but refused to sign on to the ISI. There were reports that Hamas of Iraq insurgents were involved in assisting US troops in their Diyala Governorate operations against Al-Qaeda in August 2007. In September 2007, AQI claimed responsibility for the assassination of three people including the prominent Sunni sheikhAbdul Sattar Abu Risha, leader of the Anbar "Awakening council". That same month, a suicide attack on a mosque in the city of Baqubah killed 28 people, including members of Hamas of Iraq and the 1920 Revolution Brigade, during a meeting at the mosque between tribal and guerilla leaders and the police. Meanwhile, the US military began arming moderate insurgent factions when they promised to fight Al-Qaeda in Iraq instead of the Americans.
By December 2007, the strength of the "Awakening" movement irregulars—also called "Concerned Local Citizens" and "Sons of Iraq"—was estimated at 65,000–80,000 fighters. Many of them were former insurgents, including alienated former AQI supporters, and they were now being armed and paid by the Americans specifically to combat al-Qaeda's presence in Iraq. As of July 2007, this highly controversial strategy proved to be effective in helping to secure the Sunni districts of Baghdad and the other hotspots of central Iraq, and to root out the al-Qaeda-aligned militants.
By 2008, the ISI was describing itself as being in a state of "extraordinary crisis", which was attributable to a number of factors, notably the Anbar Awakening.
Transformation and resurgence
In early 2009, US forces began pulling out of cities across the country, turning over the task of maintaining security to the Iraqi Army, the Iraqi Police Service and their paramilitary allies. Experts and many Iraqis were worried that in the absence of US soldiers the ISI might resurface and attempt mass-casualty attacks to destabilize the country. There was indeed a spike in the number of suicide attacks, and through mid- and late 2009, the ISI rebounded in strength and appeared to be launching a concerted effort to cripple the Iraqi government. During August and October 2009, the ISI claimed responsibility for four bombings targeting five government buildings in Baghdad, including attacks that killed 101 at the ministries of Foreign Affairs and Finance in August and 155 at the Ministry of Justice and Ministry of Municipalities and Public Works in September; these were the deadliest attacks directed at the new government in more than six years of war. These attacks represented a shift away from the group's previous efforts to incite sectarian violence, although a series of suicide attacks in April targeted mainly Iranian Shia pilgrims, killing 76, and in June, a mosque bombing in Taza killed at least 73 Shias from the Turkmen ethnic minority.
In late 2009, the commander of the US forces in Iraq, Genera