The Torrijos–Carter Treaties () are two treaties signed by the United States and Panama in Washington, D.C. on September 7, 1977, which superseded the Hay–Bunau-Varilla Treaty of 1903. The treaties guaranteed that Panama would gain control of the Panama Canal after 1999, ending the control of the canal that the U.S. had exercised since 1903. The treaties are named after the two signatories, U.S. president Jimmy Carter and the Commander of Panama's National Guard, General Omar Torrijos. This first treaty is officially titled The Treaty Concerning the Permanent Neutrality and Operation of the Panama Canal () and is commonly known as the "Neutrality Treaty". Under this treaty, the U.S. retained the permanent right to defend the canal from any threat that might interfere with its continued neutral service to ships of all nations. The second treaty is titled The Panama Canal Treaty (Tratado del Canal de Panamá), and provided that as from 12:00 on December 31, 1999, Panama would assume full control of canal operations and become primarily responsible for its defense. History Panamanian efforts to renegotiate the original Hay–Bunau-Varilla Treaty had been ongoing almost since it was first signed in November 1903, a few weeks after Panama obtained its independence from Colombia. However, activity to renegotiate or abrogate the treaty increased considerably after the Suez Crisis, and events in 1964 precipitated a complete breakdown in relations between the U.S. and Panama. On January 9 of that year, Panamanian students entered the canal zone to fly the Panamanian flag next to the American flag, per a 1963 agreement to defuse tension between the two countries. Panamanians watching the event began rioting after the students raising the Panamanian flag were jeered and harassed by American school officials, students, and their parents. During the scuffle, somehow the Panamanian flag was torn. Widespread rioting ensued, during which over 20 Panamanians were killed and about 500 were injured. Most of the casualties were caused by fire from U.S. troops, who had been called in to protect Canal Zone property, including private residences of Canal Zone employees. January 9 is a National Holiday in Panama, known as Martyrs' Day. The next day, January 10, Panama broke off diplomatic relations with the United States and on January 19, President of Panama Roberto Chiari declared that Panama would not re-establish diplomatic ties with the United States until the U.S. agreed to begin negotiations on a new treaty.