Two persons, including a French priest, were shot to death and opposition media were censored by authorities here today as Chilean dissidents launched the most ambitious national demonstrations ever called against the government of Gen. Augusto Pinochet.

Authorities confirmed tonight that the Rev. Andres Jarlan, living in the poor neighborhood of La Victoria, was killed during protests in Santiago tonight. Residents and witnesses in the area said Jarlan was struck by a police bullet that passed through the window of his bedroom. Another protester was killed earlier in the day in the same neighborhood.

On a day traditionally used for national elections before military rule, labor leader Rodolfo Seguel was severely beaten and Christian Democratic International President Andres Zaldivar was detained when police broke up a midday gathering by opposition figures in Santiago's central Plaza de Armas. Several other prominent politicians and labor union activists also said they were detained or beaten.

The political leaders had called on citizens to assemble in city and town centers to sing the national anthem. However, hundreds of police in riot gear supported by water cannon charged any group that sought to gather in downtown Santiago, injuring a number of protesters and bystanders and arresting dozens of others.

Zaldivar, one of Chile's most prominent political figures, was released this afternoon by special order of the Interior Ministry, a spokesman said. Seguel, a principal leader of antigovernment demonstrations in the last 16 months, was treated and released at a medical post after being carried prone from the plaza.

The noon demonstrations were meant to give impulse to a two-day national protest called by the centrist Democratic Alliance and leftist Popular Democratic Movement and dissident labor leaders.

Demonstrations began this morning in several poor Santiago neighborhoods. Police said that 250 persons had been arrested by this evening around Santiago, while church sources said at least 50 persons had been injured by police beatings.

Twelve bombing incidents were reported last night and early this morning, continuing a wave that began last week. Authorities closed four central university campuses to head off unrest.

Pinochet, who in the past has used troops to suppress demonstrations, left Santiago in control of police today while setting a midnight curfew. The military's emergency-zone command issued a decree censoring Santiago's Radio Chilena and Radio Cooperativa, the two radio stations broadcasting opposition views.

Civilian judges acted against three opposition magazines yesterday after complaints filed by the government Friday under internal security laws. Today, military authorities filed a legal complaint against the largest opposition publication, the magazine Hoy.

The measures were among the most dramatic steps in what has been a general toughening of Pinochet's rule since early this year. In recent weeks, the 68-year-old general, who will complete 11 years in power Monday, has asserted that he will not carry out plans announced last year for congressional elections in 1986 or 1987. 2 Die in Chile as Police Counter New Protests By Jackson Diehl Washington Post Foreign Service

SANTIAGO, Chile, Sept. 4 -- Two persons, including a French priest, were shot to death and opposition media were censored by authorities here today as Chilean dissidents launched the most ambitious national demonstrations ever called against the government of Gen. Augusto Pinochet.

Authorities confirmed tonight that the Rev. Andres Jarlan, living in the poor neighborhood of La Victoria, was killed during protests in Santiago tonight. Residents and witnesses in the area said Jarlan was struck by a police bullet that passed through the window of his bedroom. Another protester was killed earlier in the day in the same neighborhood.

On a day traditionally used for national elections before military rule, labor leader Rodolfo Seguel was severely beaten and Christian Democratic International President Andres Zaldivar was detained when police broke up a midday gathering by opposition figures in Santiago's central Plaza de Armas. Several other prominent politicians and labor union activists also said they were detained or beaten.

The political leaders had called on citizens to assemble in city and town centers to sing the national anthem. However, hundreds of police in riot gear supported by water cannon charged any group that sought to gather in downtown Santiago, injuring a number of protesters and bystanders and arresting dozens of others.

Zaldivar, one of Chile's most prominent political figures, was released this afternoon by special order of the Interior Ministry, a spokesman said. Seguel, a principal leader of antigovernment demonstrations in the last 16 months, was treated and released at a medical post after being carried prone from the plaza.

The noon demonstrations were meant to give impulse to a two-day national protest called by the centrist Democratic Alliance and leftist Popular Democratic Movement and dissident labor leaders.

Demonstrations began this morning in several poor Santiago neighborhoods. Police said that 250 persons had been arrested by this evening around Santiago, while church sources said at least 50 persons had been injured by police beatings.

Twelve bombing incidents were reported last night and early this morning, continuing a wave that began last week. Authorities closed four central university campuses to head off unrest.

Pinochet, who in the past has used troops to suppress demonstrations, left Santiago in control of police today while setting a midnight curfew. The military's emergency-zone command issued a decree censoring Santiago's Radio Chilena and Radio Cooperativa, the two radio stations broadcasting opposition views.

Civilian judges acted against three opposition magazines yesterday after complaints filed by the government Friday under internal security laws. Today, military authorities filed a legal complaint against the largest opposition publication, the magazine Hoy.

The measures were among the most dramatic steps in what has been a general toughening of Pinochet's rule since early this year. In recent weeks, the 68-year-old general, who will complete 11 years in power Monday, has asserted that he will not carry out plans announced last year for congressional elections in 1986 or 1987.