LINK VIENNA (Reuters) - Simon Wiesenthal, who waged an untiring campaign to track down Nazi war criminals and keep alive the memory of six million Jews killed in the Holocaust, died on Tuesday at the age of 96. Wiesenthal, a Jew and former concentration camp inmate, was best known for helping with the discovery in Argentina of Adolf Eichmann, the man Adolf Hitler entrusted with carrying out The Nazi genocide programme against the Jews. The man who helped trace some 1,100 Nazis from his small, file-crammed Vienna office, died early on Tuesday in his apartment, the Jewish Community of Vienna said. Guests from many countries are expected to attend a memorial on Wednesday. Wiesenthal will be buried in Israel. "Simon Wiesenthal acted to bring justice to those who had escaped justice," Israeli Foreign Ministry spokesman Mark Regev said. "In doing so, he was the voice of 6 million." Altogether the Nazis are estimated to have murdered at least 11 million civilians, including 6 million Jews, during World War Two. The Israeli institute named after Wiesenthal is trying to track down some 1,200 Nazis it suspects to be still alive and at large in 16 countries including Austria, Spain and Croatia. "Wiesenthal's personal mission has ended, and there are others who are carrying on with the work," said Efraim Zuroff, director of the Simon Wiesenthal Centre in Israel, on radio. Wiesenthal, born in 1908 in what is now Ukraine, travelled the world into his old age, lecturing on the Holocaust, and until last year came into his office, the Jewish Documentation Centre in Vienna, collecting data on former Nazis. He maintained that his motivation was not anger but justice. "I am someone who seeks justice, not revenge," Wiesenthal said. "My work is a warning to the murderers of tomorrow, that they will never rest." Apart from Eichmann, he helped find the SS officer who in Amsterdam arrested Anne Frank, the teenage author of the Anne Frank Diaries, and the head of the Treblinka extermination camp. His quest for Nazi doctor Josef Mengele ended when Mengele was found dead in Brazil in 1985. DETAINED IN 12 CAMPS The Germans detained Wiesenthal in Lvov in Galicia in 1941 and passed through 12 concentration camps before U.S. soldiers liberated him in the Mauthausen camp near Linz in Austria. He weighed 50 kilogrammes. Eighty-nine members of his family perished in the Holocaust but his blonde wife escaped from a camp pretending she was Polish, not Jewish. Wiesenthal said his own survival was a privilege which committed him to action. "What especially touched me was the fact that despite his personal experience, he never became bitter, and carried on in an admirable and just manner," former German Chancellor Helmut Kohl said in a statement. Wiesenthal said he began memorising perpetrators' names during his detention. A job at the War Crimes Office of the U.S. army, where he helped prepare evidence against war criminals in 1945 was the beginning of a mission that spanned six decades. Wiesenthal founded the Jewish Documentation Centre in 1947, which opened its office in Vienna in 1961. But Austria, which was annexed by Nazi Germany in 1938 and likes to portray itself as a country that was Germany's victim, was ambivalent for a long time about its famous citizen. Although Wiesenthal rejected the notion of the collective guilt of a people, he pointed out that a disproportionate number of Nazi war criminals were Austrians. He also attacked the country in the 1980s for tolerating an SS officer as minister. "Eichmann and 70 percent of his troupe as well as two-thirds of the commandants of the concentration camps were Austrians," Wiesenthal said. "And after all, Hitler was no Eskimo either." Hitler was born in Braunau, Austria, in 1889. A figure hated by neo-Nazis, Wiesenthal received threatening letters and phone calls throughout his life. After a bomb was placed outside his home in 1982, a policeman always stood guard there and before his office. But when former German army officer and Austrian presidential candidate Kurt Waldheim came under fire by the Jewish World Congress in 1986, Wiesenthal condemned the New York-based Congress for rousing anti-Semitism with its campaign. While judging Waldheim a liar for attempting to gloss over his service in the Balkans during World War Two, Wiesenthal refused to accuse him of war-crimes. Wiesenthal did not pursue specific cases in his late years but continued to help his younger co-workers and pass on his legacy. "Should history repeat itself, my example will repeat itself too... and not once, but fifty-fold," he said. "He was a soldier of justice, which is indispensable to our freedom, stability and peace." _ Terry Davis, chairman of the Council of Europe. "Simon Wiesenthal, like few others ... personally felt the shadow of history in its brutality. ... Despite this, I was always touched by the fact that he was not bitter and fought for justice admirably." _ Former German Chancellor Helmut Kohl. "I think he'll be remembered as the conscience of the Holocaust. In a way he became the permanent representative of the victims of the Holocaust, determined to bring the perpetrators of the greatest crime to justice." _ Rabbi Marvin Hier, dean and founder of the Simon Wiesenthal Center in Los Angeles. "For many, his greatest achievement was turning the phrase `Never again' from a catchy slogan into an effective international campaign against the perpetrators of genocide of all kinds, from Nazi Germany to modern Rwanda." _ Rabbi Dr. Jonathan Romain, a spokesman for the Reform Synagogues of Great Britain. "Humanity is poorer because a just man, Simon Wiesenthal, is gone." _ Hungarian Prime Minister Ferenc Gyurcsany. "We have the impression that a legendary horseman is leaving on his horse for another world." _ Nazi hunter Serge Klarsfeld, president of the Association of Jewish Deportees in France. "The name of Simon Wiesenthal ... will live on." _ Austrian President Heinz Fischer.