He also rejected a combined police force. The Dutch rejected these counter-proposals, but the concessions that Sjahrir had made cost him political support, leaving him fatally weakened. He resigned on 27 June. Sukarno then declared a state of emergency and took personal charge of the negotiations. On 29 June, van Mook wrote to Sukarno to repeat the main points that he believed must be agreed on, including continuing Dutch sovereignty and the joint police force. New Prime Minister Amir Sjariffuddin accepted the "de jure" Dutch authority, but refused to agree to the joint police force. The Dutch then also demanded an end to Republican hostilities, and the food blockade of Dutch-controlled areas by midnight on 16 July. The Republicans agreed to a ceasefire if the Dutch would also be bound by it. The Indonesian side also suggested arbitration under Article 17 of the agreement. However, on 20 July the Dutch abrogated the Linggadjati Agreement and following a recommendation by van Mook, Dutch Prime Minister Louis Beel ordered the army to commence military intervention. This began on the night of 20-21 July in form of Operation Product.