Peruvian President Alan Garcia announced in a major address tonight that the government will impose a state of emergency and a curfew in Lima to curb a fresh outbreak of urban guerrilla activity.

"Democracy is justice and tolerance, but it is also authority and repressive severity against those who wish to destroy it," Garcia said in the televised address to the nation.

Although the latest violence has not been on the same scale of previous guerrilla attacks, it is the strongest and most sustained since Garcia took office in July and comes at a time when the government has lost some of its initial political momentum.

According to the Peruvian constitution, a state of emergency can be declared for a maximum of 60 days, empowering the armed forces to take complete responsibility for maintaining public order and security. Garcia did not say how long the present state of emergency would last nor the hours of the curfew.

Although there was a brief national state of emergency declared in November 1984, during municipal elections, the last time that Lima was put under curfew was in 1978, when a military government was fighting off popular unrest.

Garcia, earlier in the day, also extended for 60 days a state of emergency already effective in 19 counties of four provinces where leftists have been fighting for five years in a guerrilla war that has claimed 6,000 lives. The decree, published in the official newspaper, El Peruano, said the emergency would continue in the southeastern provinces of Huancavelica, Apurimac and Ayacucho and the northeastern province of Huanuco.

Garcia's speech came following an upsurge of political sabotage and urban terrorism by left-wing guerrillas. For the past five years, a Maoist organization, Sendero Luminoso (Shining Path), has waged a guerrilla campaign in the Andean Sierra and Lima shantytowns. In the past year, it has been joined by another radical group, the Revolutionary Movement Tupac Amaru, which is inspired by Central American insurgents. In his speech, Garcia said he did not discard the participation of right-wing groups in the latest events because the methods pointed to "professional violence."

On Monday, five power pylons were knocked down, causing a brief blackout in Lima, and bombs damaged five precinct offices of the ruling American Popular Revolutionary Alliance party and 10 bank branches. The following day, arsonists burned down nine stores and a hotel only one block from the presidential palace in downtown Lima. Only one serious injury was reported in these incidents.

Rebel hit squads have also stepped up their activities this week, killing a former Army commander in Lima and kidnaping a Navy captain who had been posted in Ayacucho. Urban guerrillas were also active in January, bombing expensive restaurants and social clubs.

The Lima state of emergency is also believed tied to completion of the government's first stage of a radical shake-up of the 85,000-strong national police force. Yesterday, 1,179 police officers and civilian personnel were drummed out of the service, including 240 generals and colonels from the top command. Local analysts say that this reorganization has weakened the morale and preparedness of the police forces to meet a subversive threat in Lima.

In his speech, Garcia also announced economic measures to boost domestic consumption and said that the government would not devalue the Peruvian currency for the rest of the year, keeping it pegged at its August 1985 exchange rate.