Students who remained said they were in the dark 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 Columbia 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.