In conformity with the decisions taken at Oborishte, on 20 April 1876 the local rebel committee attacked and surrounded the headquarters of the Ottoman police in Koprivshtitsa commanded by Necip Aga. At least two Ottoman police officials were killed and Necip Aga was forced to release arrested Bulgarian rebel suspects. Necip Aga and his close officials managed to escape the siege. However, due to this incident the Bulgarian rebels had to proclaim the insurrection two weeks in advance of the planned date. Within several days, the rebellion spread to the whole Sredna Gora and to a number of towns and villages in the northwestern Rhodopes. The insurrection broke out in the other revolutionary districts, as well, though on a much smaller scale. The areas of Gabrovo, Tryavna, and Pavlikeni also revolted in force, as well as several villages north and south of Sliven and near Berovo (in the present-day North Macedonia).