Aiwanger is the deputy state premier of Bavaria and the head of the right-wing populist Free Voters (Freie Wähler) party, with the state set to head to the polls for a crucial election in October.
Over the weekend, the Süddeutsche Zeitung reported that he authored a distributed a leaflet that made which contained mocking references to the Holocaust when he was in high school in the 1980s.
Aiwanger's brother later said he authored the pamphlet, but the deputy state premier admitted that copies were in his school backpack.
What are the new allegations?
One former classmate told local public broadcaster Bayerische Rundfunk that Aiwanger made antisemitic jokes following a class trip to a former Nazi concentration camp. By the end of WWII, nearly 6 million Jews had been murdered by Nazi Germany and its allies.
The class trip took place in 1987, when students in the high school class visited areas of then-East Germany, including an unnamed death camp memorial.
"On one evening, I was very upset that he made a joke about Jews, which I remember as being very repulsive," the classmate, who asked to remain unnamed, told Bayerische Rundfunk.
The antisemitic remarks Aiwanger allegedly made as a teen were so offensive, that the classmate asked the news outlet not to publish them.
Aiwanger "also made a joke about children in Africa with malnourished bellies that I can remember very clearly."
"It seemed to me that Hubert found this type of humor to be very enjoyable," the classmate added.
In separate accusations revealed on Wednesday, another former classmate said the Bavarian politician at times made the Hitler salute when entering classrooms in high school.
The classmate told public broadcaster ARD that Aiwanger "very often imitated these Hitler speeches in this Hitler slang" and that he had "definitely" made offensive, hateful jokes about Jewish people.
How has Aiwanger responded?
The scandal has sparked considerable outrage in Germany, with sharp criticism coming from opposition parties in Bavaria.
Aiwanger denied the latest allegations against him on Wednesday, but appeared to acknowledge some poor behavior in his youth.
"It is certainly the case that in adolescence, one thing or another could be interpreted in such and such a way that is in line with the things that 15-year-old me is being accused of," the politician told broadcaster Welt TV.
"But in any case, I can say that since I reached adulthood, over the past decades, [I am] not an antisemite, not an extremist — but rather, a humanitarian," Aiwanger said.
How has the Jewish community reacted?
The Central Council of Jews in Germany sharply criticized the antisemitic sentiments expressed in the reports and expressed disappointment in Aiwanger's response to the scandal.
Josef Schuster, the president of the council, said the public conversation was no longer about whether the lawmaker learned from his past mistakes, but more about Aiwanger's "response to the allegations, which is almost defiant."
"If he belonged to certain groups in his youth where this type of rhetoric and these views were common, a willingness to address the situation should be especially important considering his current position," Schuster told the daily mass-circulation Bild newspaper.
"He owes it to the public," he added.
Scandal in run-up to Bavaria elections
The growing antisemitism scandal comes at a tense moment, as Bavaria prepares to head to the polls to elect a new state parliament on October 8.
Aiwanger's Free Voters are in a junior coalition with state premier Markus Söder and his conservative Christian Social Union (CSU).
Söder has so far stuck by Aiwanger and has not dismissed him. He did, however, asked Aiwanger to answer 25 questions over the initial allegations on Monday, saying that he would evaluate further after getting the answers.
Söder also stressed that "there is no place for antisemitism" in Bavaria's state government.
The regional political scandal has also raised eyebrows on the federal level — with Chancellor Olaf Scholz and other members of his government calling for clarification and potential consequences.
"All that has become known so far is very depressing. And that is why it is very clear to me that everything must be clarified," Scholz told his Cabinet on Wednesday.
rs/jcg (dpa, AFP)