In its most confrontational act against the administration yet, Fossil Free Yale made the question of divestment impossible to ignore.

On Thursday, 48 members of FFY entered Woodbridge Hall, the seat of the Yale administration, and staged a sit-in demanding that the University reconsider divestment. This step marks renewed escalation by the group, which has previously worked through formal administrative channels and in recent months, had turned to such techniques as petitions and picketing. But Thursday’s demonstration — which culminated in 19 students being threatened with arrest and receiving infraction tickets — places Yale alongside other universities where the question of divestment has become even more fraught in recent months.

“There have been a lot of sit-ins this semester, and Yale is the first school to have arrested its students,” FFY Communications Coordinator Chelsea Watson ’17 said. “Other schools have let their students stay there.”

While the University maintains that the punitive measures by the Yale Police Department were not arrests and students were not booked, members of FFY maintain that they were told they would be arrested and therefore did not resist further.

Across the country, student activists have staged demonstrations, with varying degrees of pressure and success, calling upon their respective universities to divest from the fossil fuel industry. In February, Divest Harvard — Harvard’s equivalent of FFY — stormed Massachusetts Hall, which houses Harvard President Drew Faust’s office. This demonstration lasted over 24 hours before students vacated the building.

Jasmine Opie, a junior at Harvard and one of the Divest Harvard co-coordinators, said that during their sit-in protests, members of the group came face-to-face with university administrators, who condemned their protest as “disrespectful and coercive interference.” However, unlike Yale, Harvard administrators did not force students to leave the building after normal operating hours.

“Similar tactics have not caused administrators to respond in this way at any of the other schools that have been doing sit-ins,” Opie said.

She added that during the spring, there has been a very “intentional and thought out” decision among student divestment groups around the country to escalate the pressure of campaigns and directly confront university administrators. Divest Harvard plans to hold a weeklong sit-in later this month, and will launch a five-day “Heat Week” event on Monday, which is designed to bring together students, alumni, members of the Harvard community and other advocates for divestment.

Beyond Yale and Harvard, other student groups at universities across the nation have led to increased demonstrations against the administrations of their respective schools.

Swarthmore Mountain Justice — the student group leading the divestment movement at Swarthmore College — has been engaged in a sit-in since March 19 at a historic hall on campus, with no expressed intent to end the protest. As the Swarthmore sit-in stretches into its third week, dozens of Swarthmore alumni have reportedly joined the sit-in, and more than 300 alumni have pledged to withhold donations to the college until the Board of Managers — the college’s highest governing body — agrees to divest. Meanwhile, fossil fuel divestment groups at the University of Mary Washington and Bowdoin College have also staged sit-ins in recent weeks.

Still, not all student environmental groups plan to engage in confrontational measures with administrators.

Leigh Anne Schriever, a Princeton junior and president of Students United for a Responsible Global Environment, said that though SURGE is not a divestment movement, Schriever described discussion with administrators as “productive” on issues of sustainability on campus. She added that she is aware of the recent demonstrations at Harvard and Yale, and hopes student activism does not “get to that point” at Princeton.

Thursday’s sit-in follows a series of protests held on Beinecke Plaza that culminated in a March 5 letter demanding the University formulate a plan to “address the multiple injustices created by the fossil fuel industry” by midnight on April 1, or face “escalated direct action” by the group.

“Yale just demonstrated to us pretty clearly whose side they are on and it is not our side,” FFY member Lex Barlowe ‘17 said

This is not the first time that Yale students have faced consequences for occupying a University building in protest. In 2005, a group of students staged a sit-in at Yale’s Admissions Office to demand reform to the University’s financial aid policies. When the protestors did not leave, police officers cited students for simple trespassing, and fined them $92 — the same amount Thursday’s protestors now face. Further, during anti-apartheid divestment protests in the 1980s, students were arrested for staging a sit-in inside Yale’s investment office.