Elements of an armored regiment of the Chilean Army led by Lieutenant Colonel Roberto Souper tried to overthrow the Popular Unity government of President Salvador Allende.

Souper's regiment fired on buildings of the Chilean Government in central Santiago with tanks and small arms in which 22 people were killed.

The Tanquetazo was unsuccessful but is considered to have weakened Allende's Popular Unity government and contributed to the successful 1973 Chilean coup d'état three months later.

By the beginning of June 1973, an important part of the high command of the Chilean Armed Forces had lost all respect for the Popular Unity government of President Salvador Allende, which had been in office since November 1970.

The government immediately arrested nine people involved in the conspiracy, and Minister Tohá decided to go public with this information on the afternoon of 28 June.

While filming the events outside La Moneda, Argentine cameraman Leonardo Henrichsen and his colleague Jan Sandquist were fired at by corporal Héctor Hernán Bustamante Gómez and several soldiers.

[1] Earlier that morning, Salvador Allende spoke to the people of Chile from the presidential residence at Tomas Moro in Santiago.

In a 9:30 AM radio address, the president announced his unequivocal decision to defend the constitutional government against an attempted coup d'état.

[1] Driving toward La Moneda, General Prats thought about the likely effects of these actions on other military units, who might be participating or, at least, waiting to act until they had seen the initial results.

Colonel Julio Canessa arrived with forces from the Junior Officers' Academy, and General Prats ordered pieces of heavy artillery be deployed along the principal Avenue.

[1] Souper surrendered later that day, after units from the 1st Artillery Regiment "Tacna" encircled and fired on the 2nd Armored barracks where he and his troops had taken refuge.

Other military officers involved in planning the putsch were René López, Edwin Ditmer, Héctor Bustamante, Mario Garay, Carlos Martínez, Raúl Jofre, and José Gasset.

Pablo Rodríguez Grez, John Schaeffer, Benjamín Matte, Manuel Fuentes, and Juan Hurtado sought asylum in the Embassy of Ecuador.

The failure allowed the conspirators to check loyalties, and push the government to take steps towards an alliance with the Christian Democracy party.

[3] Christian Democracy's leader Patricio Aylwin demanded the formation of a coalition cabinet, to include members of the armed forces.