Police and private security throng every entrance but one. Steel barriers line the streets. Students pack up belongings in their cars and leave for home – classes are cancelled, and exam plans are up in the air.

Everywhere there is gloom, and uncertainty about what happens next at Columbia University.

Students told the BBC that the university’s decision to call in police to clear a Gaza protest late on Tuesday, leading to a raid on the occupied Hamilton Hall and hundreds of arrests, has left the college community shattered.

The university president, Nemat Shafik, said that it was with great regret that she ordered the police raid against students and others she said had infiltrated the protest. It would “take time to heal”, she added in a message in the operation’s aftermath.

For students of this prestigious school in Manhattan, New York, how long is unclear.

“It definitely feels like things are scattered,” said Anna Oakes, a graduate journalism student at Columbia University who covered the removal of protesters from Hamilton Hall on Tuesday evening. “There’s this feeling of scramble in the aftermath.”

After a night of chaos and confrontation, the clearest reminder of the protests on Wednesday morning were water-logged flyers littering streets alongside the campus perimeter. One promised that protest organisers “will not stop. We will not rest”.

Students who remained said they were left mystified about plans for their finals and even whether dining services would be brought back fully.

While others speed off in cars packed with possessions, Will Parkinson, a 20-year-old environmental studies student, described his feeling: “Weird limbo”.

“We’re not sure what to do,” he said, and recounted how he watched from a friend’s dorm window as police stormed Hamilton Hall.

He had been barred from leaving the building during the raid, which meant he was unable to get home and finish a term paper.

Mr Parkinson said the school had given students money to spend at nearby restaurants because they had to limit staff who would normally operate the university’s cafeterias.

He had left campus to eat, and was not sure when he would eventually write that paper.

Others continued to peacefully protest, walking near the new steel barriers, holding slogans including “Cops off campus” and “Student power v Israel power”.

Members of the faculty, whose access to campus and offices is now largely denied, said they did not know how they were expected to conclude the semester.

“I have students who can’t get to their work study to pay for school, I have faculty members with papers they need to grade locked in their offices, I have 16 instructors looking to me for guidance on how to support students through finals and the end of the semester,” said Joseph Howley, a classics professor who has worked with the student protesters.

“So it has completely upended everything we do.”

Unable to address those academic obligations, Prof Howley led dozens of students and faculty members in a protest outside the one campus entrance left unobstructed on Wednesday afternoon.

He and others said that the university administration had lost their trust by bringing police on to campus, and that they shouted “shame” in unison when Prof Shafik’s name was mentioned.

One unidentified speaker at the protest said she was at Hamilton Hall when police “ambushed us. We were tackled and beaten, and my hands were handcuffed so tightly that even lifting my pinky caused extreme harm and excruciating pain”.

The NYPD denied that it was unnecessarily aggressive, and the administration has defended its decision to bring in police – who will remain on campus until 17 May.

Prof Shafik, who began serving as president in July, said on Wednesday that “tensions” on campus “rose to new heights” when protesters broke into Hamilton Hall and locked themselves inside.

She said she had acted after negotiations collapsed with demonstrators. She had given them until the early afternoon on Tuesday to disperse from a protest, and they seized the school building in response to her ultimatum.

The protesters barricaded the doors and unfurled a banner from an upper window, renaming the hall after a Palestinian child killed in Gaza – Hind Rajab. They said they would not leave until the administration agreed to divest from companies linked to Israel.

The police moved quickly after the school president invited them onto the campus, according to witnesses who spoke to the BBC.

They closed streets north and south of the school, brought in military-style equipment, barred all the school’s buildings’ doors, and broke through a chain of students who out of solidarity with the occupiers had linked arms around the perimeter of the hall.

Meghnad Bose, a 31-year-old journalism graduate student at Columbia University, witnessed the NYPD raid on Tuesday night and said police acted “rough and aggressive” with the protesters.

“There’s no doubt that the student body, not just those who were protesting, will be raising questions to the university administration about the NYPD action and the way it took place,” he said.

While 119 people at Columbia University were arrested when police stormed the school to quash the pro-Palestinian protest, police said at a Wednesday press conference that they arrested another 173 people at a similar sit-in at the City College of New York later in the evening.

Police Commissioner Edward Caban said officers intervened because “public safety was a real concern… the NYPD was called in to do their job”.

A 19-year-old physics student named Kevin – he declined to give his last name – said it was “difficult to be proud of being a Columbia student” after the police raid, which had left him deeply frustrated.

He spoke while piling bags full of clothes into his parents’ car just outside the campus gates, and said he was unsure when he would return.

“It depends on what the university does in the coming months,” he said. “We’ll see what they [the administration] say about it. The ball is in their court.”