President Augusto Pinochet, reacting sharply to the U.S. indictment of three Chilean secret police officers for murder, said yesterday that these were merely accusations and extradition will require presentation of proof.

Asked if the action against Chile's former secret police chief and two subordinates could bring down his government, Pinochet defiantly declared: "Absolutely not." He also chastised State Department officials, saying they are "involved in things they have no business getting involved in.

While Pinochet insisted in a meeting with reporters that he expects U.S. requests for extradition to be handled in conformity with Chilean law and international commitments. It was widely felt here, however, that he does noto expect the three accused to be delivered to Washington for trial.

The key responsibility for extradition falls under the jurisdiction of Chile's Supreme Court and Pinochet made it clear that he does not intend to supercede that process by personally ordering that the three be put in U.S. hands.

Extradition procedures are spelled out in a 1902 treaty between Chile and the United States. The Supreme Court, which is officially independent of the military government, is nonetheless thought to be influenced by it.

The Supreme Court, even in the days when it functioned under democratic governments, rarely has granted extradition of Chilean citizens. Furthermore, the U.S.-Chilean extradition treaty makes it clear that crimes of "a political character" are not extradictable offenses.

At the same time, however, assassination and murder are crimes for which extradition may be granted, an apparent contradiction which lawyers here said will be the basis of the legal battle that is expected once the United States formally asks for the extradition of the three former secret police officers charged with murder of Chilean exile Orlando Letelier two years ago in Washington.

If extradition is not granted, another treaty signed by both the United States and Chile provides that Chile has the obligation to try the accused here if the accusations against them are considered to be crimes under Chilean law.

Pinochet has denied since the day Letelier was assassinated that he had any personal or prior knowledge of the affair. He has continued to maintain that his government had nothing to do with it.

The Chilean president pointed out again yesterday that the charges brought against the three former officers - Gen. Manuel Contreras Sepulveda, former head of the dreaded National Directorate of Intelligence (DINA), Pedro spinoza Bravo, former director of operations at DINA, and Armando Fernandez Larios, a DINO agent who allegedly helped carry out the murder - do not constitute proof of their guilt under the U.S. system of justice.

Since it became publicly known several months ago that Contreras was under investigation, there has been widespread speculation here about whether or not Pinochet would have known about the assassination if it was in fact carried out at the instruction of Contreras - a personal friend of Pinochet's who reported directly to the president during his years as head of DINA.

It is generally believed here that only Pinochet and Contreras know for sure what the Chilean president knew before and after the assassination occurred near Sheridan Circle in Washington. Contreras' extradition and trial in the United States could prove extremely dangerous for the current Chilean government according to many observers in Santiago.

Supporters of Pinochet argue that he would never have ordered the expulsion to the United States Michael Townley last April. If he had suspected that DINA was involved in murdering Letelier, Townley, an American who worked for DINA has admitted his part in actually carrying out the Letelier assassination and has provided much of the evidence against Contreras, Espinoza and Fernandez.

The Chilean government announced Tuesday night that it had placed the three Chileans, two of whom are still active army officers, under arrest after the United States formally asked for their detention pending the formal, request for extradition.

The U.S.-Chilean treaty provides for the arrest and detention of accused persons for a period of two months when extradition is contemplated.

Pinochet stressed the two-month invitation yesterday in calling for proof.

Although the indictment of the three Chileans had been predicted for some time, the action of the grand jury in Washington on Tuesday has met with intense interest here. Groups gathered around newspaper kiosks reading newspaper headlines about the Letelier case.

Nonetheless, none of Chile's officially banned political parties issued statements or otherwise indicated reaction to the indictments - which some politicians were saying until recently could lead to the end of the military government.