Moment cops raid Portland State University's library after it was taken over by anti-Israel protesters following another night of chaos on US college campuses

This is the moment that cops in Oregon retook the library at Portland State University amid another night of fresh chaos on a college campus as authorities attempt to destroy anti-Israel encampments nationwide. 

The Millar Library at PSU had been occupied since Monday. During the clearing, police arrested at least 30 activists. 

Earlier at PSU, footage showed a student protestor crashing into a police officer while holding a makeshift shield and being arrested has emerged.

The video shows two mask-clad protestors carrying shields made out of trash cans running directly toward a police officer as people cheered in the background.  

One of the protestors is then seen crashing into the official but ends up getting knocked down to the ground. 

Elsewhere, in the pre-dawn hours, helmeted police swarmed a tent city set up at the University of California in Los Angeles, using flash bangs and riot gear to push through lines of protesters who linked arms in a futile attempt to halt their advance.

Los Angeles police said on social media that 210 people were arrested at UCLA, and hundreds of arrests were made at other universities overnight and on Thursday.

'I'm a student here,' one UCLA protester told cameras as he was led away, his hands bound. 'Please don't fail us. Don't fail us.'

Hours later, the student, who would only give his first name as Ryan, was back on campus and vowed he would not stop fighting. 

'We will be back,' said Ryan, who was cited for unlawful assembly. 'We will be disrupting. We will be demanding divestment.'

Students have rallied or set up tents at dozens of universities in recent days to protest Israel's war on Gaza. 

Demonstrators have called on President Joe Biden, who has supported Israel's right to defend itself, to do more to stop the bloodshed in Gaza and demanded schools divest from companies that support Israel's government. 

 Many of the schools, including Columbia University in New York City, have called in police to quell the protests.

Biden broke his silence on the demonstrations on Thursday after the UCLA raid, saying Americans have the right to protest but not to unleash violence.

'Destroying property is not a peaceful protest,' he said at the White House. 'It's against the law. Vandalism, trespassing, breaking windows, shutting down campuses, forcing the cancelling of classes and graduations - none of this is a peaceful protest.'

Biden, who is seeking re-election in November against Republican former President Donald Trump, has walked a careful line as he confronts criticism from both the right and the left over his Israel policy. 

At UCLA, police repeatedly urged demonstrators to clear the protest zone, which occupied a central plaza about the size of a football field, before they moved in.

Dozens of loud explosions were heard from stun grenades, fired by police, while demonstrators, some carrying makeshift shields and umbrellas, chanted 'push them back' and flashed bright lights in officers' eyes. 

Live TV footage showed officers taking down tents and tearing apart makeshift barricades.

Some of the protesters had been seen donning hard hats, goggles and respirator masks in anticipation of the siege a day after the university declared the encampment unlawful.

By morning, the plaza was strewn with detritus from the destroyed encampment: tents, blankets, food containers, a Palestinian flag, an upturned helmet. Police remained on hand during the first half of the day as the area was cleaned of debris.

In Portland, Oregon, police entered the Portland State University library on Thursday morning, where demonstrators had barricaded themselves since Monday. Several dozen protesters ran out of the building and rushed into a phalanx of officers in riot gear, who arrested them.

Police made more arrests at the library on Thursday night as demonstrators attempted to retake it. A university spokesperson said it was a 'very fluid situation.'

In New Hampshire, police arrested approximately 100 protesters in separate incidents at Dartmouth University and the University of New Hampshire overnight, breaking up encampments.

The protests follow the deadly Oct. 7 attack on southern Israel by Hamas militants from the Gaza Strip, which killed 1,200 people and saw dozens taken hostage, and an ensuing Israeli offensive that has killed about 34,000 and created a humanitarian crisis.

The campus demonstrations have been met with counter-protesters accusing them of fomenting anti-Jewish hatred. The pro-Palestinian side, including some Jews opposed to Israeli actions in Gaza, say they are being unfairly branded as anti-Semitic for criticizing Israel's government and expressing support for human rights. 

UCLA had canceled classes for the day on Wednesday following a violent clash between the encampment's occupants and a group of masked counter-demonstrators who mounted a surprise assault late Tuesday night on the tent city.

UCLA Chancellor Gene Block, in a written statement, said that officials had allowed the encampment to remain on campus for several days as it was peaceful at first, but that the clashes with the pro-Israeli crowd clearly put students in harm's way.

'It led to unsafe conditions on our campus and it damaged our ability to carry out our mission,' Block said of the encampment. 'It needed to come to an end.'

Taylor Gee, a 30-year-old pro-Palestinian protester and UCLA law student, said the police operation on Thursday felt 'especially galling' to many protesters given the slow police response a night earlier.

'For them to come out the next night to remove us from the encampment, it doesn't make any sense, but it also makes all the sense in the world,' he said.

UCLA officials said the campus, with nearly 52,000 students, would remain shuttered except for limited operations on Thursday and Friday.