Gandhiji launched Satyagraha movement against Rowlatt Act in 1919. This Act passed very fast despite the united opposition of Indian members. This Act gave enormous powers to repress political activities to the government, and allowed detention of political prisoners without any trial for two years. Rallies were organised in various cities, workers went on strike in railway workshops. British administration decided to clamp down on nationalists due to alarmed popular upsurge, and scared of that lines of communication such as telegraph and railways would be disrupted. On 10th April, the police in Amritsar fired upon a peaceful procession. This provoked widespread attacks on banks, post offices and railway stations. Martial law was imposed and General Dyer took command. After the brutal killing and massacre of Jallianwala Bagh, violence spread nationwide. The led Mahatma Gandhi to call off this Rowalatt Satyagraha movement