By Marty Graham

SAN DIEGO (Reuters) - Fraternities and sororities at San Diego State University have suspended all social activities until their members undergo sexual assault prevention training after disturbances erupted during an anti-rape march, a university official said on Wednesday.

"We've got a problem - there's a problem at universities all across the country - with sexual assault and so we are supportive of this decision by the Greek community," university spokesman Greg Block said in announcing the move.

The suspension involves 14 fraternities, but all 44 fraternity, sorority and community groups involved in the Greek system plan to participate, he said. About 3,000 of the campus' 34,000 enrolled students are part of Greek life.

The voluntary decision by the fraternities comes after a series of ugly incidents in the past week.

On Friday, a Take Back the Night anti-rape march by about 35 people from the Concerned Students and Take Back the Night groups was met by egg-throwing, sex toy-waving members of two fraternities, according to Concerned Students coordinator Jordan Busse.

Busse said that the next night, a woman was reported to have been sexually assaulted at a fraternity house. San Diego State University police confirmed there was a sexual assault report but declined to identify the fraternity involved.

"Aggressive and violent and abusive behavior from fraternity members goes unchecked," Busse said. "This year there have been 14 sexual assaults at SDSU, five of them at fraternities and not one arrest has been made."

San Diego State was one of four California public universities criticized in June for poor training and preparation of its staff to deal with sexual assault issues on campus in a statewide audit.

Training lapses at the university left staff at risk of mishandling students' reporting sexual harassment and violence, the report said.

Since the report was released, the university has aggressively trained staff and educated students about sexual misconduct, Block said. The campus's Sexual Assault Task Force will be involved in training the fraternities and sororities, Block said.

"These incidents made them realize that it is becoming critical to do something," Block said of the groups. "We're going to help them. We have lots of educational knowledge and resources to help."

(Editing by Cynthia Johnston, Alex Dobuzinskis and Eric Walsh)