Pro-Palestinian protesters at Columbia University were occupying a building on the New York City campus as officials limited access to students who live there and essential employees, Reuters reports.

The protesters occupying Hamilton Hall displayed banners from a window reading “Intifada,” the Arabic word for an uprising, CNN reported, citing a video.

The school said in an early morning notice that effective immediately access to the Morningside campus has been limited to students residing in residential buildings on campus and employees providing essential services.

“This access restriction will remain in place until circumstances allow otherwise,” it said. “The safety of every single member of this community is paramount. We thank you for your patience, cooperation and understanding.”