Former Senator Heidi Heitkamp was sitting in her second floor office at the University of Chicago’s Institute of Politics, preparing to appear on a television news show on Friday afternoon, when three pro-Palestinian protesters in masks and sunglasses burst in and ordered her to leave the building.
Ms. Heitkamp, the director of the institute and the only staff member left in the building, refused to go, slowing what had apparently been an effort to take over the building, the latest tactic in demonstrations over the Israel-Hamas war that have taken place on the University of Chicago campus and across the country.
“They desperately wanted me out,” Ms. Heitkamp recalled. “I told them, ‘I’m not going to leave. This is our building.’ And I planted my feet.” She added, “I’m a stubborn old woman.”
Ms. Heitkamp, who represented North Dakota as a Democrat in the Senate, said she tried to engage in a dialogue with the protesters about their goals and why they had targeted the institute, even as she heard others smashing furniture in other rooms.
“I was trying to find common ground,” she said. “They kept saying, ‘Aren’t you worried about your safety?’”
The confrontation ended, she said, when campus police officers suddenly arrived and some protesters, who had brought a supply of bagels and water to last for an extended period, fled out of windows.
In a statement, the protest group on Friday said that it had occupied the building to protest the University of Chicago’s ties to Israel. Bystander video showed protesters climbing through second-floor windows to leave the building, as the crowd below cheered.
After demonstrators were cleared from the building, other protesters remained outside, chanting, yelling and pounding drums. They were about two blocks from where the police removed a protest encampment last week,
Jeremy Manier, a university spokesman, said in a statement that protesters had tried to block the building’s entrance, damaged property and ignored orders from law enforcement officials to leave.
Earlier in the day, the institute held a board meeting in the building that included David Axelrod, the organization’s founder who was a senior adviser to President Barack Obama.
Mr. Axelrod and Ms. Heitkamp issued a statement later in the day, “We recognize protest as a time-honored part of the democratic process. But the occupation of buildings, destruction of property and impingement on the rights of others are not.”
Ms. Heitkamp said she never felt threatened by the protesters who had appeared in her office, nor did she feel that she was being held hostage. “They knew who I was — they called me senator, “ she said. “They just really wanted me to leave.”
“I tried to explain that we are a place of dialogue at the I.O.P.,” she said.
“We’re neutral,” she said, adding, “Our role at the university is to really create a space for cross dialogue.”
The Institute of Politics is two doors away from the University of Chicago Hillel and across the street from Rohr Chabad, where some students were having a Sabbath dinner when the demonstration began. As the protest continued, counterprotesters held Israeli flags within sight of the pro-Palestinian demonstrators. Rock music blasted from a nearby house, in what appeared to be an effort to drown out the protest chants.
A sign identifying the Institute of Politics building was covered with a cardboard placard that read “permanent cease-fire now,” and a set of demands were hung from the building. Among the demands was “abolish the university.”
A group of protesters at the University of Pennsylvania also tried on Friday evening to occupy a campus building. The university police and the Philadelphia police made several arrests and cleared the building, Fisher-Bennett Hall. The hall is across the street from College Green, the site of the encampment that was cleared last week by the police.
Mattathias Schwartz, Bob Chiarito, Jeremy W. Peters and Natalie Pompilio contributed reporting.