The Public Broadcasting Service's plan to show a debate after its documentary in April on the Ottoman Turks' massacres of Armenians has infuriated Armenian-Americans. The debate, which includes two people who deny that the massacre constituted genocide, has ignited an aggressive campaign against the network.

This week, United States Representative Adam B. Schiff, Democrat of Pasadena, Calif., whose Southern California district includes parts of the largest ethnic Armenian population outside Armenia, asked colleagues to join him in a letter to the network condemning the program.

A major Armenian lobbying group, the Armenian National Committee of America, has also asked PBS to cancel the program, which was produced by Oregon Public Broadcasting to accompany a new one-hour documentary, "The Armenian Genocide," scheduled to be shown on April 17. Organizers of an Internet petition against the half-hour discussion program said more than 11,000 people had signed it on the Web site.

In the latest twist to the controversy, the PBS station in Los Angeles, KCET-TV, said Thursday that it would broadcast neither the discussion program nor the documentary, making it difficult for most of the nearly 400,000 Armenians in the Los Angeles area to see either one. The station said it would show two other films dealing with the killings, mollifying some Armenians here.

PBS said that its 348 affiliates would decide independently whether to carry the film or the panel discussion and that it would not keep track of the decisions. Stations in Washington and in Plattsburgh, N.Y., which reaches the large Armenian community in Montreal, said they would run the film but not the panel discussion, while stations in Chicago and New York said they would run both.

Few topics among Armenians generate as much passion as the deaths of some 1.5 million Armenians by execution, starvation or disease during a World War I era campaign by Turks in the Ottoman Empire to wipe them out. Armenians have lobbied for decades for worldwide recognition of the atrocities as genocide.

Most historical accounts accept this view, but the Turkish government has denied for years that the deaths were a result of a state-directed effort to exterminate the Armenian people and argued that the Armenian death toll has been inflated — and some historians agree.