WASHINGTON — Campus police at George Mason University are investigating two cases of sexual assault reported during the first week of classes.

The assaults occurred over the Labor Day weekend in residence halls at the Fairfax, Virginia, campus and are believed to be separate incidents, according to university officials.

“It’s on all of us to end sexual violence,” the George Mason University President Ángel Cabrera wrote in a statement. “We need to address it publicly, discuss it actively, and work together to eradicate it.”

The school sent out crime alerts to the students, letting them know what happened.

Cabrera said everyone in the university community “must commit to doing something when we see something.”

“We cannot simply be bystanders. We must make it clear to all around us that nonconsensual sex is unacceptable,” he wrote.

Cabrera said Vice President for University Life Rose Pascarell is working to get additional information to students about sexual assault prevention services that are available on campus.