BERLIN, Aug 7 -- Two Jewish cemeteries have been desecrated in the western German state of Rhineland-Palatinate and an explosive device has been found outside a Jewish family's home in Bavaria, the police said today.

The incidents contributed to a climate of mounting concern in Germany over anti-Semitic and anti-immigrant violence by rightists. The attacks are not new, and they reflect the activities of a small minority, but evidence that racist criminals are now better armed and organized has alarmed the government.

Chancellor Gerhard Schršder is currently on vacation in Majorca. But his spokesman, Uwe-Karsten Heye, met today with Paul Spiegel, the leader of the Central Council of German Jews, to promote a new initiative called "Show Your Face."

After the meeting in DŸsseldorf, where a bomb last month wounded nine immigrants, six of them Jews, Mr. Heye said an advertising campaign would begin next month in which famous Germans, including sports and film celebrities, would exhort the nation to show zero tolerance for racists. "We want to encourage people to do something against xenophobia and anti-Semitism," he said.

Last week, Foreign Minister Joschka Fischer said Germans had been too silent in the face of rightist violence. His statement struck a chord in a nation where the need for "Zivilcourage" -- personal courage rooted in a strong moral conscience -- has been exhorted as an essential quality since the Third Reich demonstrated the dangers of passivity.

Mr. Spiegel said Germans must act together to isolate and undermine rightist agitators, whose propaganda has thrived particularly in the formerly Communist east. Among many youths, often socially alienated and without work, shaved heads, racist slogans, black-leather attire and paramilitary discipline have proved an appealing route to an elusive sense of identity and togetherness.

"As many people as possible have to say we don't want to let a group of outlawed madmen destroy what we've built up over the past 55 years," Mr. Spiegel said. Several recent incidents, including the latest, have occurred in western Germany, suggesting that rightist groups may be broadening their appeal.

Up to now, the Schršder government had given scant attention to rightist violence, concentrating its efforts on deregulating the German economy. But it has become clear to Mr. Schršder that his aim of making Germany a competitive "global player" -- to use a phrase in vogue in his coalition -- is scarcely compatible with repetitive outbreaks of nationalist thuggery.

In the latest incidents, a total of 11 graves in the villages of Rockenhausen and Dielkirchen, near Kaiserslautern, were desecrated. The police said Nazi swastikas and SS slogans were daubed on headstones in light gray paint.

The desecration of Jewish cemeteries is not uncommon in Germany. Last year more than 100 headstones were smashed or overturned in Berlin's Weissensee cemetery, and Julius Schoeps, an expert on German Jewish affairs, said that there had been more than a thousand cases of desecration in the post-war years.

There are about 2,300 Jewish cemeteries in Germany, reflecting centuries of Jewish presence in a country where more than 500,000 Jews lived before Hitler's rise to power. In many places, particularly smaller towns and villages, these cemeteries constitute the last trace of Jewish life in the area.

In the northern Bavarian town of Bamberg, police officers found an explosive device outside a Jewish family's home after it was spotted by a neighbor. "After recent incidents, people have become more vigilant," a police spokesman said.