His body was discovered by officers at about 7am on Thursday at the apartment complex.

In a letter posted by USC senior vice-president Elizabeth Garrett on the university website, officials stressed the death "was an isolated incident and there was, and is, no apparent threat to the campus community".

Pete Foster, an officer with the university's Department of Public Safety, added that "any area around USC is really safe".

But some students pointed to a history of deadly violence on or near the campus.

"It's shocking, but at the same time you're almost desensitised because you're like, 'Are you kidding me? It happened again?'" said Joe Benson, a senior undergraduate student.

He challenged campus police to develop more effective security methods and to stop "pretending they have it under control." He added: "What they're doing now isn't working."

USC poured considerable resources into improving safety after a series of shootings.

In April 2012, two 23-year-old Chinese graduate students in the electrical engineering programme were shot dead while sitting in a parked BMW just west of the campus. The news raced through American and Chinese-language social networking sites, with questions raised about students' safety.

USC routinely enrols thousands of international students, among the largest number of any college in the US.

The parents of two students, Ying Wu and Ming Qu, later filed a wrongful death lawsuit against the university, saying the school misled them when it claimed it ranks among the world's safest.

Six months later, a gunman opened fire in a crowd outside a Halloween party near the centre of USC. Four people were wounded and the campus was placed on lockdown.