The Interfraternity Council has called a halt to all social activities at USC fraternities Saturday after the Department of Public Safety announced it received not only allegations of sexual abuse and drugs being slipped into drinks during parties at Sigma Nu fraternity, where chapter President Ryan Schiffilea has been confirmed by police as a sexual assault suspect, but also at other fraternities.

“Ryan Schiffilea is a suspect but has not been arrested. This is an ongoing investigation,’” Los Angeles Police Department Officer Rosario Cervantes told City News Service.

DPS announced Saturday that it will enforce the Interfraternity Council’s Safety Notification, which prohibits fraternities from hosting on-campus social activities indefinitely.

“The university has also taken steps to increase security and enhanced supervision on and around 28th Street,” DPS said.

The campus police department’s Oct. 20 Daily Incident Log lists five reports dating back to Sept. 27 of students claiming to have been slipped a mickey at parties at the Sigma Nu house, 660 W. 28th St., and another report of a student being drugged at a party at an unknown location. It also lists a report of a sexual assault at the Sigma Nu frat house.

DPS did not name the other fraternities listed as the subject of allegations.

USC President Carol Folt has suspended a student in connection with some of the allegations, the Los Angeles Times reported.

“Such behaviors are deeply disturbing, they hurt people and go against everything we stand for as a community,” Folt wrote in an email to the USC community and obtained by the Times. “We are sorry for the pain and anguish this is causing.”

It was unclear whether Schiffilea was the suspended student.

On Friday, students marched outside the Sigma Nu house and some plastered notes referencing the alleged sexual assaults.

“You are all complicit,” said one note.

Earlier in the week, the university placed Sigma Nu — whose motto is “Excelling with Honor” — on interim suspension, forbidding it from hosting or organizing any activities, parties or other social gatherings at the fraternity house.

USC reported the allegations and chapter suspension to Sigma Nu’s national headquarters, which responded: “The fraternity is concerned by these serious allegations and will seek to work with university officials to investigate the matter. The fraternity will determine its further actions based upon the investigation.”

The campus police urged anyone with information about alleged assaults to call 213-740-6000 for the University Park Campus (UPC), 323-442-1000 for the Health Sciences Campus (HSC) or 213-485-6571 for the LAPD Southwest Division.

Calls to the LAPD during non-business hours or on weekends can be made to 877-527-3247 and anonymous tips can be called in to Crime Stoppers at 800-222-8477 or submitted online at lacrimestoppers.org.