Hostilities between Libya and Egypt increased greatly in April-May 1977, when demonstrators in both countries attacked each other's consulates. Colonel Muammar al-Qaddafi (1943-), Libya's head of state, accused Egypt of provoking a war so that it could seize the Libyan oil fields, a charge Egypt denied. In June 1977, Qaddafi ordered the 225,000 Egyptians working and living in Libya to leave the country by July 1 or face arrest. An exchange of gunfire by troops along the Libyan-Egyptian border on July 21, 1977, immediately caused a four-day war, in which both sides used tanks and airplanes in several battles along the desert border. A number of Libyan aircraft were destroyed on the ground during an Egyptian strafing attack. After Algeria's president intervened as a peacemaker both sides agreed to a cease-fire on July 24, 1977; both countries had suffered heavy losses of men and material.