The JNA learned about Croatia's intention to develop its own military force from JNA Captain Vladimir Jager, a double agent employed by Croatia and the JNA Counterintelligence Service (KOS). The JNA devised Operation Shield ("Štit"), aimed at disarming the Croatian forces and the arrest and trial of the Croatian leadership, in response. Although the operation was prepared by December 1990, federal Defence Minister General Veljko Kadijević never sought authorisation to carry it out from the Yugoslav Presidency. Instead, he ordered the KOS to stand down on the morning the operation was scheduled to begin.