The Comintern was involved in the revolutions across Europe in this period, starting with the Hungarian Soviet Republic in 1919. Several hundred agitators and financial aid were sent from the Soviet Union and Lenin was in regular contact with its leader Béla Kun. Soon, an official Terror Group of the Revolutionary Council of the Government was formed, unofficially known as Lenin Boys. The next attempt was the March Action in Germany in 1921, including an attempt to dynamite the express train from Halle to Leipzig. After this failed, the Communist Party of Germany expelled its former chairman Paul Levi from the party for publicly criticising the March Action in a pamphlet, which was ratified by the Executive Committee of the Communist International prior to the Third Congress. A new attempt was made at the time of the Ruhr crisis in spring and then again in selected parts of Germany in the autumn of 1923. The Red Army was mobilized, ready to come to the aid of the planned insurrection. Resolute action by the German government cancelled the plans, except due to miscommunication in Hamburg, where 200–300 Communists attacked police stations, but were quickly defeated. In 1924, there was a failed coup in Estonia by the Estonian Communist Party.