Christian Democrat Vinicio Cerezo assumed office today as Guatemala's first civilian president since 1970. In an impassioned address, he condemned the widespread violence and economic difficulties of his nation in recent years.

Foreign dignitaries, including Vice President Bush, attended in a display of support. Cerezo offered to host negotiations to resolve Central America's conflicts.

"It is certain that we find a country in the worst conditions that any chief executive ever has found in this nation," Cerezo said. He did not specifically criticize the outgoing military government, and he appealed for cooperation from all sectors of the 8 million population.

Cerezo made clear, however, that he believed the armed forces and the nation's wealthy bore much of the responsibility for the tens of thousands of deaths since the late 1970s, and for the extreme disparity of income between rich and poor.

The tough tone of Cerezo's speech suggested that he would not shy away from confrontation with the powerful military establishment and conservative business community. He won a landslide victory over his center-right opponent.

Cerezo, 43, stressed that the previous string of military governments were not legitimate representives of the people.

"We are a people who were thrown out of our house, and today we return," he said. "We are a people who were denied expression, and many of us were persecuted for telling the truth."

Outgoing chief of state Gen. Oscar Mejia Victores, who sat on the stage, did not join in the repeated rounds of applause that interrupted Cerezo. In a speech just before the inauguration, the general pointed out that he had delivered on a promise to preside over the election of a civilian government.

Cerezo paid "patriotic homage" to Guatemalans killed in the bitter conflict between the armed forces and a rural Marxist insurgency. Most of the killing was by the armed forces, which often were accused of failing to distinguish between armed guerrillas and real or suspected leftist sympathizers.

In a last-minute decree that apparently was designed to prevent prosecution of anyone responsible for the killings, the military government over the week-end declared a general amnesty for anyone accused of crimes committed since March 1982, which includes the period of the last two military governments.

It was not immediately clear what effect the decree would have, and some Christian Democrats said that the national legislature had the power to overturn the decree if it wished.

"Thousands of Guatemalans have died in this frightening turn to violence," Cerezo said. Some had used violence "in defense of privileges and prerogatives that they have always enjoyed," while others used it because they "did not see another way to defend their rights and demands," he added.

Cerezo reserved some of his harshest language for the economic policies of previous governments, but did not outline a program of his own.

"There has been incompetence in management of public administration, and corruption," he said.

Attending the inauguration were three presidents -- fellow Christian Democrat Jose Napoleon Duarte of El Salvador, Daniel Ortega of Nicaragua and Belisario Betancur of Colombia -- plus president-elect Jose Azcona of Honduras.

Cerezo was to host a breakfast of the presidents to try to breathe life into the Central American peace process.