The backs of New York police officers standing guard outside the gates of the Manhattan campus could be seen through the railings. Police surveillance drones appeared in the dusk sky.

Even as one drone hovered over a two-week-old tent encampment set up on a lawn by students protesting Columbia's financial ties to Israel's war in Gaza, Columbia administrators summoned student leaders to a Zoom meeting on Tuesday. That last discussion was unsuccessful.

Within hours, police had arrested dozens of people on burglary and trespassing charges, including at least 30 students, six alumni and two Columbia employees, and cleared out protest encampments that had spawned dozens of similar demonstrations at colleges around the world.

This account of the night police swarmed the Ivy League university campus is based on interviews with student protesters, professors, bystanders and the eyewitness accounts of Reuters journalists.

Hours before police moved in, protesters occupying Hamilton Hall appeared on its second-floor balcony above the barricaded front doors. Most wore Columbia-logo sweatshirts and black balaclavas. One reclined on the balcony's outer wall, dangling a leg over, offering peace signs to a crowd of supporters below and a middle finger to student journalists raising a microphone as high as they could for comment.

Students used a pulley to raise pizza, water, first-aid supplies and a large plank of wood up to the balcony. Each successful ascension drew cheers. Shouts of "We love you!" were swapped between the balcony and the plaza below.

TEN MINUTES TO DECIDE

Since the morning, Columbia had locked down the main campus, restricting it to undergraduates living on campus, security and dining-hall staff and other essential workers.

Sueda Polat, a graduate student getting a degree in human rights and one of the lead negotiators with school administration on behalf of the protesters, got onto campus by sneaking through a basement and pleading with a security guard. She sang along with a choir of protesters assembled before the barricades, a soft unison of mostly female voices: "We shall not be moved."

Robbie Fox, a fourth-year undergraduate biology major leaning against a nearby pillar, was unmoved. He disagreed with the protesters' demands and had lost patience with their escalating tactics.

"When you refuse to compromise, you can't control what happens after that," he said.

Around 7 p.m. Polat and her co-negotiator, Palestinian graduate student Mahmoud Khalil, sat at a laptop on the ground outside the lawn encampment to speak with Columbia administrators, who the day before had declared an impasse and suspensions for protesting students.

The students' primary demand was that Columbia divest from companies that support Israel's government and military. Columbia's president said the university would not "divest from Israel" but would ensure their proposals received expedited review by the school's divestment advisory committee.

The counteroffer was still on the table, the administrators told the pair, if the remaining students in the lawn encampment agreed to leave immediately. Columbia administration, which declined interview requests, refused to discuss the fate of the students occupying Hamilton, Polat and Khalil said.

They had 10 minutes to decide. They again refused the deal.

"It was a non-starter," Polat said. She and Khalil believed Columbia would let in the police however they responded.

'INVADING ARMY'

At 8:18 p.m. crowds of students drifting about the campus were galvanized by their phones: "Shelter in place for your safety," said an email from Columbia Emergency Management. "Non-compliance may result in disciplinary action."

At 9:07 p.m. Columbia's southern gates opened and scores of police with helmets and armor marched in. Sheila Coronel, a professor at Columbia's journalism school who had covered protests in her native Philippines, said it resembled an "invading army." Coronel was there to oversee and feed the dozens of student journalists trying to cover the extraordinary scene.

"Shame on you!" chanted students, a mix of protesters and undergraduate bystanders, yelling anti-police insults as they scattered. Advancing officers, wielding batons, shouted at everyone to move back from the Hamilton doors.

With police circling, Polat told a few journalists that in five years Columbia would say it was proud of the protesters. Then she disappeared in the commotion.

Within minutes, police had cleared everyone from outside Hamilton, ordering most students into a dormitory before barring the doors with batons through the handles. Security staff said anyone who did not live in the dorm must stay in the lobby. Dozens did. Some continued yelling at police, others were in tears. Students across campus were threatened with arrest if they sought to step outside.

A few remaining journalists, student and otherwise, were ordered out of a southern gate.

Police threw the upturned furniture blocking the Hamilton entrance down the steps and severed the bike chains locking the doors. Through the trees, students at upper-floor windows could see and hear flash-bangs going off inside Hamilton. One officer inside, trying to aim a flashlight on his gun, accidentally fired a bullet, hitting a wall, police said.

Some politicians had demanded that Columbia have police quash anti-Israel protests for the safety of Jewish students like Jacob Gold, an undergraduate who for hours watched the events through a sixth-floor dormitory window.

He was not part of the protests, though he had been curious about the encampment, walking by it frequently, and had friends inside. He said Tuesday night was the first time he had felt in danger, "and it was because of the police."

Deputy Police Commissioner Tarik Sheppard stood among the tents to film for a short video police would release the next day: "This is not a tent city, this is New York City," he said into the camera. "And if you're thinking about doing something like this, take a look around, see how fast we clear it out."

Not far from the encampment, a silent Polat hid from police behind a gate column with a friend for over an hour. She recorded video of dozens of handcuffed protesters from Hamilton, including friends, being marched past her by police onto the jail vans. To her, they appeared "still unbeaten, still joyous, still disciplined, still principled."