Vienna, Austria ? Former U.N. chief Kurt Waldheim, who was barred from the United States for two decades after revelations he belonged to a German army unit that committed World War II atrocities, died Thursday. He was 88.

Although it was never proved that Waldheim personally committed war crimes, he left public life beneath a cloud of disgrace and died with his name still on a watch list prohibiting foreigners considered undesirables from visiting the U.S.

Waldheim’s legacy as U.N. secretary-general in 1972-81 – and his later tenure as Austrian president in 1986-92 – was tarnished by his secretive wartime past in the Balkans.

The details did not become common knowledge until five years after he left the world body. But the revelations led to a bruising controversy at home – one that ultimately damaged Austria’s reputation abroad. During Waldheim’s six-year term as president, the country was largely shunned by foreign leaders.

His past began surfacing early in his campaign for president, when he published a memoir that did not mention his service for the Nazis. In his official biographies, Waldheim initially said he had been wounded at the Russian front in 1941 and had returned to Austria to continue his studies.

Only after being confronted with documents showing his unit had killed partisans and civilians, along with allegations that the victims included thousands of children, did Waldheim gradually revise his resume.

He acknowledged he was transferred to the Balkans in April 1942, went to Greece as an interpreter that summer and, in April 1943, became an assistant adjutant with Army Group E, Department I-C. Its commander, Gen. Alexander Loehr, was later executed in Yugoslavia for war crimes.

Waldheim consistently maintained his innocence, defending himself against disclosures made by his main accuser, the World Jewish Congress, and by foreign media.

As pressure mounted from all sides, Yugoslav newspapers published a facsimile of a 1947 document showing Waldheim’s name on a list of German officers who took part in the infamous Mount Kozara operation. According to some Yugoslav versions, 68,000 people – including 23,000 children – died in the offensive.

Waldheim originally said he had been behind the lines near Kozara. Later, he said he had confused the geography.