(NewsNation) — Pro-Palestinian protesters picketed at Columbia University on the first day of classes for the fall semester, resuming the demonstrations that touched off a wave of similar action at colleges nationwide.

On Tuesday morning, the Associated Press reported dozens of protesters were outside the school’s entrances, some beating drums.

“We refuse to live in a world where the mass murder of Palestinians is normal, acceptable, and profitable. Columbia University is complicit in genocide,” Columbia Students for Justice in Palestine said on X. “Their investments in weapons manufacturers & defense contractors, companies such as Lockheed Martin, are fueling the genocide.”

More than 40,000 people have died in Israel’s offensive in Gaza, which started after Hamas-led militants killed 1,200 people and took 250 hostages on Oct. 7.

“The death and destruction we’re seeing in Gaza is funded by @Columbia’s investments,” CU Apartheid Divest said on X.

Tuesday’s protests come a month after the resignation of Columbia’s former president Minouche Shafik, who faced widespread criticism over her handling of antisemitism and Islamaphobia on campus.

Shafik was also condemned for bringing the New York Police Department on campus to clear out protest encampments. Hundreds were reportedly arrested, and students described feeling unsafe because of the presence of armed law enforcement on school grounds. At one point, students took over a campus building, hanging a sign out the window saying they renamed it “Hind’s Hall.” That name is in honor of  Hind Rajab, a little girl killed in the Gaza Strip by Israeli forces.

Katrina Armstrong, who took over the presidency in the interim after Shafik’s departure in August, said she has met with students on both sides of the issue, according to the Associated Press.

A spokesperson for Columbia told the AP that the university has bolstered its guidelines around protests and developed new training for incoming students on antisemitism and Islamophobia.

NewsNation crews on Tuesday observed school campus officers checking people into Columbia, with long lines forming of people waiting to get in, as well as new signs prohibiting camping. As part of new restrictions put into place by Columbia, the campus gates are closed and access is restricted to those with university ID cards and their pre-registered guests.

Columbia officials say if anyone wants to come in and protest or put a tent on the ground, they’ll have to face consequences if they don’t have a permit.

The Associated Press contributed to this report.