Between December 16 and 19, 1998, Clinton ordered four-day period of concentrated air attacks against military installations in Iraq. This was in response to Saddam's refusal to cooperate with UN inspectors. After the bombing, Hussein blocked any further UN inspections and announced its attempt to shoot down Coalition aircraft in the no-fly zones over Iraq. For several years afterward, U.S. and Coalition aircraft routinely attacked hostile Iraqi defense installations in Iraq, in response to what the Clinton administration claimed were "provocations" by the Iraqi military, including antiaircraft fire and radar locks on U.S. and Coalition aircraft.