In October 1927, Trotsky and Zinoviev were expelled from the Central Committee. When the United Opposition tried to organize independent demonstrations commemorating the 10th anniversary of the Bolshevik seizure of power in November 1927, the demonstrators were dispersed by force and Trotsky and Zinoviev were expelled from the Communist Party on 12 November. Their leading supporters, from Kamenev down, were expelled in December 1927 by the XV Party Congress, which paved the way for mass expulsions of rank-and-file oppositionists as well as internal exile of opposition leaders in early 1928.