At this point, on 17 July 1979 Somoza Debayle resigned from office and fled the country by plane to Miami, FL., followed suit by almost all the senior military officers of the GN General Staff. Somoza's successor as head of state, interim President Francisco Urcuyo Maliaños opened negotiations for a cease-fire but at the same time tried to strengthen his political position by filling with younger colonels and lieutenant-colonels the depleted National Guard's General Staff, now headed by the new Chief Director Lt. Col. (later General) Federico Mejía González. The 12,000 Guardsmen still under his command, now besieged in the government quarter of Tiscapa hill at Managua and Managua International Airport, and at the remaining holdouts throughout the country were exhorted to continue the fight.