The new civilian government will set up a commission to find out what happened to hundreds of persons who "disappeared" during previous military rule, but it will not prosecute officers for past political crimes, Guatemalan President Vinicio Cerezo said today.

The government plans to revive an offer of amnesty for left-wing guerrillas, and it would be politically "naive" to imprison officers while pardoning the insurgents, Cerezo said in an interview.

"We cannot condemn one side of the confrontation, put the Army officers in jail, and forgive the guerrillas," Cerezo said, adding that to do so would be "to continue the confrontation."

Cerezo said he sent letters last weekend to several U.S. congressmen asking the United States to increase economic aid to Guatemala this year to help it meet an unusually high level of short-term debts left by the military government. He asked for $130 million in grants and loans, compared to $82.6 million approved for the current fiscal year ending in September.

Cerezo disclosed his plan to create an "impartial" commission to investigate disappearances during a 45-minute interview at the National Palace. He was responding to pressure by the Mutual Support Group, an organization of relatives of persons who vanished during the recent years of conflict between leftist guerrillas and security forces.

Thousands of real or suspected leftists were killed or abducted during that period, and the armed forces and police are widely accused of being responsible for most of the unresolved cases.

The Mutual Support Group, at a meeting with Cerezo earlier this month, asked him not only to form an investigative commission but to prosecute those responsible for the presumed killings. It presented him with 959 cases of "disappearances" between 1980 and 1985, and with names of about 100 military and police officials whom it said were responsible.

Cerezo said today that the commission would "investigate the fate of the people who disappeared," in particular to determine if any were still alive in secret prisons. But he stressed that his government can take responsibility for guaranteeing human rights only since it took office Jan. 14.

Even if he wanted to prosecute Army officers, Cerezo said, he believed that he lacked the legal instruments to do so. The previous government issued a decree in its closing days declaring an amnesty for anyone accused of political crimes during the preceding two military governments.

The Mutual Support Group and some legislators want to overturn that decree. But Cerezo said that he "believed" that it was too late to do so legally, and in any case it would be politically unwise to alienate the armed forces.

"We face the political decision of pardoning everybody, or of continuing the confrontation. You cannot ask the democratic government to carry out acts of political naivete," he said.

Citing efforts since his inauguration to protect human rights, Cerezo said that one Army "specialist" of undisclosed rank and two civilians had been arrested for recent attacks on members of Cerezo's Christian Democratic Party in an eastern town. Five alleged guerrillas also have been arrested in a separate case and will be put on trial, he said.

Referring to his request for increased U.S. assistance, Cerezo said he was giving top priority to economic rather than military aid. Congress has approved a $4.7 million grant for Guatemala for nonlethal military aid, such as spare parts and medical equipment, but the law says that the money cannot be disbursed until the Guatemalan president formally requests it.

Cerezo said he planned to accept the military aid, but he would not ask for it for "several months" because he wanted to emphasize the need for economic assistance.

"Economic aid is what is really needed for the consolidation of democracy," Cerezo said. "If we do not begin a process of development, the people are going to begin a process of making demands that will lead us to a social confrontation."