of insurgent groups came from a variety of sources. Former members of the security services of the Ba’ath regime, former military officers, and some other Ba’ath Party members are cited as members of insurgent groups; indeed, these elements formed the primary backbone of the nascent insurgency. Initially, most former members of the Ba'ath Party and former Iraqi soldiers expressed a willingness to compromise with the Coalition forces. However, many lost their jobs and pensions with the disbanding of the Iraqi army by Bremer; this, and the unwillingness of the Coalition Provisional Authority to negotiate with former Ba'ath elements, provided impetus for the initial insurgency. While 80% the officers were Sunni, the rank and file of the regular army was 80% Shia. Prisoners released from prison by Saddam Hussein before his disappearance provided another source both of insurgent recruits and of organized crime factions. Finally, as O’Hanlan says, the porous borders of Iraq and the subsequent foreign insurgents also bolstered the insurgency. History Insurgency begins (May–June 2003) In May 2003, after the Iraqi conventional forces had been defeated and disbanded, the U.S. military noticed a gradually increasing flurry of attacks on U.S. troops in various regions of the so-called "Sunni Triangle", especially in Baghdad and in the regions around Fallujah and Tikrit. These consisted of small groups of suspected guerrillas firing assault rifles and rocket-propelled grenades, in addition to using basic forms of IEDs (Improvised Explosive Device) on U.S. patrols and convoys in attacks that were often poorly planned and demonstrated poor marksmanship and training. In many cases the insurgents were killed in the return fire. The U.S. military blamed the attacks on remnants of the Ba'ath Party and the Fedayeen Saddam militia. It seems that many of these attacks were "potshots" from disaffected former members of the Iraqi military. Tensions between U.S. forces and the residents of Fallujah were especially severe, with crowd riots and small skirmishes commonplace. Coalition response and counterinsurgency (June–September 2003) In response to the attacks taking place, on June 9, the U.S. military launched Operation Peninsula Strike, in which 2,000 soldiers from Task Force Iron Horse swept through the Tigris River peninsula of Thuluiya in the Sunni Triangle, detaining 397 Iraqis. Almost all of the detainees were later released, and the operation failed to stem the tide of the assaults. A series of similar operations were launched throughout the summer in the Sunni Triangle, such as