BOGOTA, Colombia (AP) _ Two gunmen shot and killed a Colombian journalist and three farmers she was interviewing, the latest victims in a wave of assassinations, officials said Tuesday.

Silvia Duzan, a free-lance reporter, was killed Monday night in a cafe in Cimitarra, were she was working on a story on right-wing death squads, said Salvador Pardo, the town's mayor.

The town, 75 miles north of Bogota, has been the scene of dozens of assassinations by right-wing death squads.

Ms. Duzan was the sister of Maria Jimena Duzan, a newspaper columnist who often writes about drug traffickers and the death squads they finance. At the time of her sister's death, she was in New York City to appear in a panel discussion, ''Freedom of the Press Under Siege Overseas,'' at Columbia University's Graduate School of Journalism. Pardo said the men slain with Ms. Duzan were directors of the Carare Agricultural Workers' Association. He identified the three as Jouse Vargas, Saul Castaneda, and Miguel Barajas, and said they were leading a campaign to reduce violence in the region.

''They had all been threatened with death,'' the mayor said. He did not say who was behind the threats.

A friend of Ms. Duzan's said on condition of anonymity the reporter had been carrying out an independent investigation of violence in the region. It was not immediately clear who she was working for.

In the past, reporters were told in Cimitarra that leftist guerrillas and right-wing death squads have been active in the region for years.

The town is located in the heart of the central Magdalena River region, a base for paramilitary groups backed by drug traffickers. The groups have killed more than 1,000 people in the last four years, according to the attorney general's office.

Drug traffickers who bought large stretches of land in the area have cooperated with other wealthy farmers in a campaign of violence against leftist guerrillas and peasant farmers suspected of supporting them.

According to human rights investigators, members of the Colombian military also have perpetrated massacres, torture and other atrocities in a war against union and cooperative organizers, leftist leaders, judges and journalists.

Four years ago, a death squad killed 36 peasants near Cimitarra.

Ms. Duzan's death brought to 49 the number of journalists assassinated in Colombia since 1977.

The killings in Cimitarra were the latest in a wave of political violence that included the slaying of three city councilmen and a mayor. Nine died in battles between the army and leftist guerrillas.

Unidentified gunmen on Monday shot and killed Martinez Mendoza, a city councilmen in Murindo, 240 miles north of Bogota, the Antioquia state police said.

Campos Pinilla, a councilman in northwestern Muzo, was killed Monday by gunmen in a bar he owned there, the Boyaca state government office said. The Cauca state police said Lasso Martinez, a councilman in El Bordo, 250 miles south of Bogota, was killed on Saturday by a gunman.

Five men on Monday kidnapped and killed the 31-year-old leftist mayor of Apartado, Diana Cardona, police said.