Launching the movement in May 1966 with the help of the Cultural Revolution Group, Mao soon called on young people to "bombard the headquarters", and proclaimed that "to rebel is justified". In order to eliminate his rivals within the CPC and in schools, factories, and government institutions, Mao charged that bourgeois elements had infiltrated the government and society with the aim of restoring capitalism. He insisted that revisionists be removed through violent class struggle, to which China's youth, as well as urban workers, responded by forming Red Guards and "rebel groups" around the country. They would begin to hold struggle sessions regularly, and grab power from local governments and CPC branches, eventually establishing the revolutionary committees in 1967. The groups often split into rival factions, however, becoming involved in 'violent struggles' (), to which the People's Liberation Army had to be sent to restore order.