Israeli Prime Minister Ehud Barak urged a new generation of German leaders today to stamp out right-wing extremism and other forms of antisemitism so that the horrors of Nazi genocide are never repeated.

Making the first visit by a foreign leader to the German capital since the government returned here over the summer, Barak and Chancellor Gerhard Schroeder visited the Sachsenhausen concentration camp north of Berlin. There, Barak said Germans have an historic obligation to block the rising xenophobic movements before they become a threat to democracy.

"Here and on other battlefields . . . Germany committed the greatest crime in human history," Barak said as he stood near a crematorium built by the Nazis in 1943. "Never before was a scientific and systematic attempt made to carry out genocide against an entire people."

Barak declared that "you have a duty to crush any National Socialist [Nazi] and antisemitic bud . . . before it bears dangerous fruit."

Schroeder sought to reassure Barak that his government feels a special responsibility to protect human rights and was determined to combat the racism and other forms of extremism exhibited by many alienated young people, particularly in eastern Germany.

"We owe it to the dead, but also to ourselves and our children, that we win the fight against hate and contempt for humanity and lay a secure basis for a peaceful future," Schroeder said. "We must remind ourselves and everyone else, there must never again be another Sachsenhausen. Never again Treblinka. Never again Auschwitz, any place on earth."

Germany is considered Israel's closest ally after the United States, and successive German governments have supplied strong political and economic support, including $50 billion in reparations and other aid for the 250,000 Holocaust survivors who settled in Israel.

Barak used his visit to impress upon Schroeder the need to put greater pressure on German companies to pay overdue compensation to World War II slave laborers, who included many non-Jews from Eastern Europe, before they die.

The negotiations are set to resume in Washington in early October, but the companies and lawyers defending the estimated 2.3 million former laborers in a class-action suit remain badly divided in their calculations as to how much money should be paid. The German firms have offered to put $1.7 billion into a common fund; the lawyers say at least $20 billion will be needed to properly compensate the former slaves.

In their talks, Schroeder promised Barak that his government would strive to persuade the companies to improve their offer and reach a settlement as quickly as possible so that the first payments could be made before year's end, German officials said.