An insurrection in Dublin when some 2000 members of the Irish Volunteers and the Irish Citizen Army took up arms against British rule in Ireland. The Irish Republican Brotherhood had planned the uprising, supported by the Sinn Fein Party. A ship carrying a large consignment of arms from Germany was intercepted by the British navy. Roger Casement of the IRB, acting as a link with Germany, was arrested soon after landing from a German U-boat. The military leaders, Pádraic Pearse and James Connolly, decided nevertheless to continue with the rebellion. The General Post Office in Dublin was seized along with other strategic buildings in the city. The Irish Republic was proclaimed on 24 April, Easter Monday, and a provisional government set up with Pearse as President. British troops forced their opponents to surrender by 29 April. The rising had little public support at first. Many Irishmen were serving in British forces during World War I. 16 leaders of the rebellion were executed and over 2000 men and women imprisoned. The executions led to a change of feeling in Ireland and in the 1918 general election Sinn Fein won the majority vote.