The rebellion of the crews of the ships and the garrison of the fortress of Kronstadt (Kotlin Island) in March 1921, caused by dissatisfaction with the dictatorship of the Bolsheviks and their policy of War Communism.
Late February saw rallies held on Kronstadt’s largest military ships, the battleships Petropavlovsk and Sevastopol, at which sailors demanded to clarify the state of affairs in Petrograd, where factories were swept by demonstrations and political strikes. A delegation of sailors sent there reported that the authorities were putting pressure on the workers. On March 1, 16,000 sailors, Kronstadt garrison, and residents gathered on Yakornaya Square. The rally adopted a resolution to demand immediate re-election of the Soviets by secret ballot, freedom of speech for workers and peasants, anarchists and left-wing socialist parties, and the abolition of the emergency food policy, primarily the Prodrazvyorstka [food requisition]. The Bolsheviks were accused of the replacement of the Soviet power with “commissarism [power of commissars]”, which was reflected in the slogan “All power to the Soviets, not to the parties!” On March 2, the Provisional Revolutionary Committee was established in Kronstadt, which took full power in the city. The Bolshevik leadership declared the action a counter-revolutionary White Guard mutiny, refused to negotiate, and demanded immediate and unconditional surrender. To suppress the rebellion, troops were sent to Kronstadt.
The first offensive of the Red Army units, undertaken on the night of March 7–8, failed. In the following days, the troops of the Workers' and Peasants' Red Army along the shores of the Gulf of Finland and in Petrograd were significantly reinforced. Delegates of the 10th Congress of the Russian Communist Party (Bolsheviks), RCP(b), communists from different regions, prominent Party and state leaders led by the chairman of the Revolutionary Military Council of the Republic, Leon Trotsky, were engaged to suppress the uprising. March 17–18 saw a decisive assault take place, as a result of which Kronstadt was taken. As a result of hostilities and subsequent repression several thousand people died. About 8 thousand rebels were able to flee to Finland across the ice of the Gulf of Finland.
At a time of the uprising, the 10th Congress of the RCP(b), held in Moscow from March 8 to 16, decided to replace the Prodrazvyorstka with prodnalog [Tax in Kind], which laid the foundation for a New Economic Policy that eased the economic situation of broad strata of the population.