the end of August 1966, almost every Chinese city and a majority of counties had Red Guard activity. Eighty-five percent of counties had local Red Guard activity by October 1966. According to sociologist Andrew G. Walder, "These figures represent a remarkable level of popular political mobilization. At no point in the previous history of the regime were ordinary citizens permitted, much less encouraged, to form independent political organizations." Due to the factionalism already emerging in the Red Guard movement, President Liu Shaoqi made the decision in early June 1966 to send in Chinese Communist Party (CCP) work teams. These workgroups were led by Zhang Chunqiao, head of China's Propaganda Department, in an attempt by the Party to keep the movement under control. Rival Red Guard groups led by the sons and daughters of cadres were formed by these work teams to deflect attacks from those in positions of power towards bourgeois elements in society, mainly intellectuals. In addition, these Party-backed rebel groups also attacked students with 'bad' class backgrounds, including children of former landlords and capitalists. These actions were all attempts by the CCP to preserve the existing state government and apparatus. Mao, concerned that these work teams were hindering the course of the Cultural Revolution, dispatched Chen Boda, Jiang Qing, Kang Sheng, and others to join the Red Guards and combat the work teams. In July 1966, Mao ordered the removal of the remaining work teams (against the wishes of Liu Shaoqi) and condemned their 'Fifty Days of White Terror', a label referencing the period of time the work teams were active. The Red Guards were then free to organize without the restrictions of the Party and, within a few weeks, on the encouragement of Mao's supporters, Red Guard groups had appeared in almost every school in China. Chiang Kai-Shek believed Mao lost trust in CCP officials and members, Communist Youth League of China (CYLC) members, and even workers, peasants and soldiers, so he had put faith in the students, and made use of the Red Guards to preserve his authority. Role in the Cultural Revolution Red August Mao Zedong expressed personal approval and support for the Red Guards in a letter to Tsinghua University Red Guards on 1 August 1966.<ref name=autogenerated1>(Chinese){{Cite web |url=http://dangshi.people.com.cn/GB/85039/14329784.html |title=倪天祚, "毛主席八次接见红卫兵的组织工作" 中国共产党新闻网 |trans-title=Chairman Mao received the organization of the Red Guards eight times. |last=Ni |first=Tianqi |date=7 April 2011 |website=people.com.cn |access-date=27 December 2011 |archive-date=1 October