STUTTGART, Germany (AP) _ Josef Schwammberger, a former Nazi labor camp commander, went on trial Wednesday for the brutal murders of more than 3,000 people during World War II.

About a dozen neo-Nazis protested outside the court building and later heckled Nazi hunter Simon Wiesenthal, who attended the opening session of what may be the last major war crimes trial in Germany.

Schwammberger, 79, was a Nazi SS lieutenant who commanded slave labor camps in Poland, where thousands of inmates were interned and died. He escaped to Argentina after the war and lived there until he was extradited to Germany in May 1990.

He is charged with 12 counts of murder in the deaths of at least 43 people and 40 counts of accessory to murder in the slayings of 3,374 people. Most of the victims were Jews.

Justice officials say Schwammberger has never denied working at the camps. But they say he claimed to have shot only one prisoner ''because of special circumstances'' and denied any role in other killings.

Conviction could bring a life sentence.

Prosecutor Kurt Scrimm said Schwammberger acted out of ''contempt for Jewish people and racial hatred.''

Among other crimes, he is accused of killing a rabbi who refused to work on Yom Kippur; of setting his German shepherd dog on a young girl and watching her bleed to death from bites; of murdering, along with his unit of pro-Nazi Ukrainian troops, at least 40 Jewish orphans and burning their bodies.

Wiesenthal, who had put Schwammberger on his list of 10 most-wanted war criminals, said: ''He committed enormous crimes, crimes that cannot be punished. His sentence should be 30 times life, 50 times life, for every murder he committed,. He murdered out of greed, he killed for enrichment. He killed for pleasure.''

Outside the court, about a dozen neo-Nazis held up a large red banner inscribed: ''Freedom for Schwammberger.'' One used a bullhorn to protest against the trial, while others distributed leaflets.

About 20 neo-Nazis, some wearing combat boots, were among about 100 people attending the trial.

They laughed loudly when Chief Judge Herbert Luippold said Schwammberger would receive an ''absolutely fair trial,'' but quieted down after the judge threatened to eject and fine them.

Schwammberger, a short, balding man, walked into court slowly and with difficulty, holding onto tables as he approached the defendant's chair.

Because of his health, Schwammberger can attend only brief sessions twice a day. The opening session lasted 90 minutes and the afternoon hearing about two hours.

Judge Herbert Luippold questioned Schwammberger about his youth and his reasons for joining the Nazi party.

Often speaking slowly and in broken sentences, Schwammberger said he joined the Nazi party and went to Germany from his native Austria in search of a better job. He said he shared the Nazis' admiration for ''law and order.''

Schwammberger was arrested in Austria in July 1945, but escaped from detention in January 1948 and reached Argentina in March 1949.

He stressed he had never hidden his identity while living in Argentina.

''I never went into hiding, that was propaganda,'' he said. ''I always used my name.''

The trial, expected to last several months, continues Friday.