Dozens of masked anti-Israel protesters stormed Columbia University’s Butler Library as students prepared Wednesday to study for end-of-year exams.

Video posted on social media shows a large group of activists shoving past a security guard at the library’s front entrance, who tried in vain to stop the mob but was quickly overcome.

Once inside, they draped large signs over bookshelves , one declaring the library a “liberated zone” and another bearing the name of Bassel al-Araj, a Palestinian activist killed by Israel Defense Forces in a 2017 raid in the West Bank — though they misspelled his first name as “Basel.”

Here is the latest on the Barnard College and Columbia University student protests

The raucous demonstrators then donned keffiyeh headscarves, and beat drums while clapping to chants of “free, free Palestine.”

The school has been on alert since rumors circulated late last month that protesters were planning on re-establishing the campus tent encampments that plagued the Ivy League school for much of last spring .

This is a developing story. Please check back for updates.