The Buffalo Police Department said that a student had been seriously injured early Friday in what it was calling an "incident of potential hazing."
"BPD are investigating an incident of potential hazing that occurred at a fraternity house in Buffalo overnight on Custer Street," the department said in a tweet. "A UB student was rushed to the hospital with a serious medical condition believed to have resulted from the Incident."
The student was identified on Saturday by UB officials as 18-year-old Sebastian Serafin-Bazan, of Port Chester, New York.
The news was followed by an immediate suspension of all Greek life at the college in western New York.
"As the investigation into this very serious matter continues, let me reiterate that our university has zero tolerance for hazing," University at Buffalo President Satish Tripathi said in a statement. "Not only are hazing incidents a violation of our university policies, but they are also crimes.
"Therefore, at my direction, the official activities of all recognized fraternities and sororities are suspended effective immediately," he added.
On Sunday, the school announced that it will launch an internal review of all Greek life.
"An internal review committee, formed by UB Vice President for Student Life A. Scott Weber, will examine each organization’s health and safety educational programs, policies and practices, with a special focus on anti-hazing," the university said in a statement.
The incident happened at the school's Sigma Pi house, according to a statement from the frat.
"Sigma Pi has recently learned of a reported allegation of health & safety policy violations at Epsilon-Omicron Chapter at the University at Buffalo," Jonathan Frost, executive director and CEO of Sigma Pi Fraternity & Foundation, said in a statement. "At this time, we are currently gathering information and, if necessary, will provide further comment after all facts have been gathered."
Serafin-Bazan is currently in critical condition and on life support at Buffalo General Hospital, according to Buffalo ABC affiliate WKBW.
"The University at Buffalo community is deeply concerned about the health and well-being of our student whose injuries, Buffalo Police suspect, may have resulted from hazing overnight," the university said in a statement. "We are in contact with the student’s family and will provide whatever assistance and comfort we can during this very difficult time, as we hope for the very best for our student who is an undergraduate student at UB."
Neighbors said they saw two frat members carry a person out of the house overnight after authorities arrived.
"This is a family neighborhood, there's families that live in these houses," Adam Rodriguez told WKBW. "Obviously, thank God there were no kids out here at that time because I believe that could have been a pretty traumatic experience. Even me, just seeing the body here ... that was pretty hardcore."
A Sigma Pi student at Ohio University died after an alleged hazing incident in November. The family of that student, Collin Wiant, filed a wrongful death lawsuit against Sigma Pi and another 10 unnamed individuals in February.
ABC News' Aliki Shinas and Vera Drymon contributed to this report.