A professor who said he jokingly called for the mass killing of whites has received death threats and a stern warning from his bosses at Drexer University in Philadelphia. George Ciccariello-Maher, associate professor of politics and global studies, started the controversy over demographics when he tweeted to his nearly 11,000 Twitter followers Saturday, "all I want for Christmas is white genocide."

Conservative websites and activists demanded Drexel dismiss Ciccariello-Maher over the tweet, which they described as a call to violence. The Daily Caller claimed the professor had a long history of being racist “towards white people on Twitter.” “White genocide” has become code in the white nationalist movement for diversity, multiculturalism, immigration and high birth rates about non-whites.

But Ciccariello-Maher said he was was making a political point about racism, not calling for mass killings. In a follow-up tweet on Christmas, he said, “To clarify: when the whites were massacred during the Haitian Revolution, that was a good thing indeed.”

Drexel has distanced itself from the tweet. "Drexel became aware today of Associate Professor George Ciccariello-Maher's inflammatory tweet, which was posted on his personal Twitter account on Dec. 24, 2016. While the university recognizes the right of its faculty to freely express their thoughts and opinions in public debate, Professor Ciccariello-Maher's comments are utterly reprehensible, deeply disturbing, and do not in any way reflect the values of the university," a statement Monday read. "The university is taking this situation very seriously. We contacted Ciccariello-Maher today to arrange a meeting to discuss this matter in detail."

More than 3,500 people, including many scholars, have signed a petition calling on Drexel to protect Ciccariello-Maher's freedom of speech, Inside Higher Ed reported Monday. "Preserve academic freedom (and wit and intelligence and anti-racism) in this nasty new era of living in the United States of internet trolls," the petition reads. "Support George. Let Drexel know -- in the midst of the deafening, organized troll-storm -- that racist trolls deserve no platform in dictating academic discourse, let alone the off-duty tweets of academics. They are being VERY noisy; we can't be silent."

Ciccariello-Maher defended his tweet in an email statement to Inside Higher Ed. "On Christmas Eve, I sent a satirical tweet about an imaginary concept, 'white genocide.' For those who haven't bothered to do their research, 'white genocide' is an idea invented by white supremacists and used to denounce everything from interracial relationships to multicultural policies (and most recently, against a tweet by State Farm Insurance). It is a figment of the racist imagination, it should be mocked, and I'm glad to have mocked it," Ciccariello-Maher wrote. "What I am not glad about is that this satirical tweet became fodder for online white supremacists to systematically harass me and my employer, Drexel University. Beginning with Breitbart.com ... and running through the depths of Reddit discussion boards, a coordinated smear campaign was orchestrated to send mass tweets and emails to myself, my employer, and my colleagues. I have received hundreds of death threats."

Responding to Drexel's statement, he said: "While Drexel has been nothing but supportive in the past, this statement is worrying. While upholding my right to free expression, the statement refers to my (satirical) tweets as 'utterly reprehensible.' What is most unfortunate is that this statement amounts to caving to the truly reprehensible movements and organizations that I was critiquing. On the university level, moreover, this statement -- despite a tepid defense of free speech -- sends a chilling message and sets a frightening precedent. It exposes untenured and temporary faculty not only to internal disciplinary scrutiny, but equally importantly, it encourages harassment as an effective means to impact university policies."

He added: "White supremacy is on the rise, and we must fight it by any means. In that fight, universities will need to choose whether they are on the side of free expression and academic debate, or on the side of the racist mob."

Ciccariello-Maher’s website describes him as a writer and radical political theorist whose academic specialties include “race and racism.”