El Tanquetazo or El Tancazo (both Spanish for "tank putsch") of 29 June 1973 are the names used to refer to the failed coup attempt in Chile led by Lieutenant Colonel Roberto Souper against the government of Socialist president Salvador Allende. It is called such because the rebelling officers primarily used tanks. It was successfully put down by loyal Constitutionalist soldiers led by Army Commander-in-Chief Carlos Prats.