In early January 1993, the UN Special Envoy Cyrus Vance and EC representative Lord Owen began negotiating a peace proposal with the leaders of Bosnia's warring factions. The proposal, which became known as the "Vance-Owen peace plan", involved the division of Bosnia into ten semi-autonomous regions and received the backing of the UN. The President of the Republika Srpska, Radovan Karadžić, signed the plan on 30 April. However, it was rejected by the National Assembly of Republika Srpska on 6 May, and subsequently referred to a referendum. The plan was rejected by 96% of voters, although mediators referred to the referendum as a "sham". On 18 June, Lord Owen declared that the plan was "dead".