An outspoken Drexel University professor known for stirring controversy on Twitter over current events, including October's mass shooting in Las Vegas, is leaving the school.

George Ciccariello-Maher, an associate professor of politics and global studies, will "no longer work" at Drexel after Dec. 31 due to continued threats made against him, he said in a statement posted on social media Thursday.

"This is not a decision I take lightly; however, after nearly a year of harassment by right-wing, white supremacist media outlets and internet mobs, after death threats and threats of violence directed against me and my family, my situation has become unsustainable," he said in the statement. "Staying at Drexel in the eye of this storm has become detrimental to my own writing, speaking, and organizing."

In the lengthy post, Ciccariello-Maher went on to comment on free speech on college campuses, remarking that "we are at war, and academia is a crucial front in that war."

Ciccariello-Maher also included messages to faculty and his students, who he said have "earned [his] admiration and the admiration of many by standing up for [their] rights."

"In the face of aggression from the racist Right and impending global catastrophe, we must defend our universities, our students, and ourselves by defending the most vulnerable among us and by making our campuses unsafe spaces for white supremacists," he wrote in the Thursday afternoon message.

Ciccariello-Maher was placed on administrative leave in October after making controversial comments on social media on Oct. 2, a day after 64-year-old Stephen Paddock opened fire on a crowd of music festivalgoers in Las Vegas, killing 58 people and injuring nearly 500.

"White people and men are told that they are entitled to everything," Ciccariello-Maher wrote Oct. 2. "This is what happens when they don't get what they want."

Ciccariello-Maher also raised eyebrows with comments in March that took on the U.S. military, saying it made him want to "vomit or yell" to see a airline passenger give up a first-class seat to a service member. He first drew ire when he tweeted on Christmas Eve 2016 that all he "wanted" for the holidays was a "white genocide." He later said that the comment was posted as satire.

The university had said it decided to place Ciccariello-Maher on leave to protect its students, faculty, and staff, but previously defended the professor's decision to express his own opinions.

Drexel confirmed that Ciccariello-Maher had resigned, citing his decision "to pursue other opportunities."

"Drexel University has accepted his resignation and recognizes the significant scholarly contributions that Professor Ciccariello-Maher has made to the field of political thought and his service to the Drexel University community as an outstanding classroom teacher," the university said in a statement. "Drexel University wishes Professor Ciccariello-Maher well in his future pursuits."

Ciccariello-Maher did not respond to a request for comment.

Staff writer Rob Tornoe contributed to this article.