Supreme Court's resolution Given that he had armed organized his own paramilitary forces, this was a call to violent reprisals against the opposition, which were implemented. The Chilean Army opposed this coup, and acted against Allende. When Allende was deposed, the Chilean left began a terror campaign. From Wikipedia:
On 26 May 1973, Chile’s Supreme Court unanimously denounced the Allende régime’s disruption of the legality of the nation
in its failure to uphold judicial decisions. It refused to permit police execution of judicial resolutions that contradicted the Government's measures.
 Chamber of Deputies' resolution
On 22 August 1973, with the support of the Christian Democrats and National Party members, the Chamber of Deputies passed 81–47 a resolution that asked "the President of the Republic, Ministers of State, and members of the Armed and Police Forces"
to "put an immediate end" to "breach[es of] the Constitution . . . with the goal of redirecting government activity toward the path of Law and ensuring the Constitutional order of our Nation, and the essential underpinnings of democratic co-existence among Chileans."
The resolution declared that the Allende Government sought ". . . to conquer absolute power with the obvious purpose of subjecting all citizens to the strictest political and economic control by the State . . . [with] the goal of establishing a totalitarian system", claiming it had made "violations of the Constitution . . . a permanent system of conduct." Essentially, most of the accusations were about the Socialist Government disregarding the separation of powers, and arrogating legislative and judicial prerogatives to the executive branch of government.
Specifically, the Socialist Government of President Allende was accused of:
Finally, the resolution condemned the creation and development of government-protected [socialist] armed groups, which . . . are headed towards a confrontation with the armed forces.
- ruling by decree, thwarting the normal legislative system
- refusing to enforce judicial decisions against its partisans; not carrying out sentences and judicial resolutions that contravene its objectives
- ignoring the decrees of the independent General Comptroller's Office
- sundry media offences; usurping control of the National Television Network and applying ... economic pressure against those media organizations that are not unconditional supporters of the government...
- allowing its socialist supporters to assemble armed, preventing the same by its right wing opponents
- . . . supporting more than 1,500 illegal ‘takings’ of farms...
- illegal repression of the El Teniente miners’ strike
- illegally limiting emigration
President Allende's efforts to re-organize the military and the police forces were characterised as notorious attempts to use the armed and police forces for partisan ends, destroy their institutional hierarchy, and politically infiltrate their ranks
It can be argued that the resolution called upon the armed forces to overthrow Allende if he did not reform, as follows "...To present the President of the Republic, Ministers of State, and members of the Armed and Police Forces with the grave breakdown of the legal and constitutional order ... it is their duty to put an immediate end to all situations herein referred to that breach the Constitution and the laws of the land with the goal of redirecting government activity toward the path of Law " 
 President Allende's response
Two days later, on 24 August 1973, President Allende responded,
characterising the Congress's declaration as destined to damage the country’s prestige abroad and create internal confusion
, predicting It will facilitate the seditious intention of certain sectors
. He noted that the declaration had not obtained the two-thirds Senate majority constitutionally required
to convict the president of abuse of power: essentially, the Congress were invoking the intervention of the armed forces and of Order against a democratically elected government
and subordinat[ing] political representation of national sovereignty to the armed institutions, which neither can nor ought to assume either political functions or the representation of the popular will
Allende argued he had obeyed constitutional means for including military men to the cabinet at the service of civic peace and national security, defending republican institutions against insurrection and terrorism
. In contrast, he said that Congress was promoting a coup d’état
or a civil war with a declaration full of affirmations that had already been refuted before-hand
and which, in substance and process (directly handing it to the ministers rather than directly handing it to the President) violated a dozen articles of the (then-current) Constitution. He further argued that the legislature was usurping the government's executive function.
President Allende wrote: Chilean democracy is a conquest by all of the people. It is neither the work nor the gift of the exploiting classes, and it will be defended by those who, with sacrifices accumulated over generations, have imposed it . . . With a tranquil conscience . . . I sustain that never before has Chile had a more democratic government than that over which I have the honor to preside . . . I solemnly reiterate my decision to develop democracy and a state of law to their ultimate consequences . . . Parliament has made itself a bastion against the transformations . . . and has done everything it can to perturb the functioning of the finances and of the institutions, sterilizing all creative initiatives
Adding that economic and political means would be needed to relieve the country's current crisis, and that the Congress were obstructing said means; having already paralyzed
the State, they sought to destroy
it. He concluded by calling upon the workers, all democrats and patriots
to join him in defending the Chilean Constitution and the revolutionary process
The insurgency against the government precipitated the repressions against the terrorists and their supporters. This is something that the left invariably leaves out of its outraged recollections of Pinochet. They also forget that Pinochet stepped down voluntarily and submitted to free elections, something that only one communist government has ever done (and the Sandinistas were forced to concede only because the sheer volume of their loss could not be hidden from the international observers and the Bush administration would not permit them to ignore the results).
After the coup, left-wing organizations tried to set up resistance groups against the regime. Many activists created groups of resistance from refugees abroad, while the Communist Party of Chile
set up an armed wing, which became in 1983 the FPMR
(Frente Patriótico Manuel Rodríguez
). In the first three months of military rule, the Chilean forces recorded 162 military deaths.
A total of 756 servicemen and police are reported to have been killed or wounded in guerrilla incidents.
The Movimiento de Izquierda Revolucionaria
(Revolutionary Left Movement
, MIR) founded at the University of Concepción
suffered heavy casualties in the coup's immediate aftermath, and most of its members fled the country.