LOS ANGELES (AP) — Pro-Palestinian demonstrators took over a building Wednesday at California State University, Los Angeles, where campus police were monitoring the situation as employees inside shelter in place, an official said.

University spokesperson Erik Frost Hollins said a group of 50 to 100 people barricaded exits on the first floor and blocked paths around the building, so the university asked employees to shelter in place, The Los Angeles Times reported. The university president’s office is in the building, but he wouldn’t confirm whether she was one of the people inside.

The university posted a “protest action alert” on its website announcing that all main campus classes and operations would be remote until further notice and asking people not to go to the main campus.

Images from the scene showed graffiti on the building, furniture blocking doorways and overturned golf carts, picnic tables and umbrellas barricading the plaza out front.

The CSULA Gaza Solidarity Encampment, a group that has camped near the campus gym for about 40 days, sent an email indicating that members were staging a sit-in in the building, Hollins said. Campus police “are aware and they are in the area,” he said.