President Joe Biden has addressed the protests, saying students have the right to protest but not "cause chaos"
His remarks come after police officers broke down barricades to clear a pro-Palestinian protest at the University of California in Los Angeles (UCLA)
Hundreds of people with tents had set up encampments at UCLA - officers told them to move or face arrest
Overnight, hundreds of officers entered the site and by Thursday morning most protesters had gone
Our reporters saw dozens of detained protesters with their hands behind their back, being put on buses
On Tuesday night, a masked pro-Israeli group assaulted a pro-Palestinian student camp, before officers were called to the campus
Demonstrations are continuing at dozens of universities across the US; there have been more than 1,000 arrests in total
Officers have been at UCLA since Wednesday morning, warning protesters that they would be arrested if they did not leave.
While we're yet to get official confirmation of any arrests, tensions appear to be heating up now.
Watch as officers attempt to advance into the protest encampment, as our correspondent Helena Humphrey reports from the campus:
Cai Pigliucci
Reporting from UCLA
Image source, ReutersThere are chants of “leave our campus” echoing throughout the streets here.
Protestors have been locking arms as they stand off with police in the distance.
Inside the encampment, protestors have been holding up images of peace signs and hearts over the barricades.
There have also been chants of “peaceful protest,” “resist at any cost” and “what side of history do you want to be on".
A hundred or so officers appear to be moving into the encampment, ripping the makeshift defences from protesters' hands and attempting to force their way through the crowd.
Others are waiting at the ready to move on.
Image source, AFPWe can see from the live feeds in the newsroom that a new force of officers has just entered the university.
Local broadcaster ABC7 says they are from the California Highway Patrol (CHP), the principal state police agency for the state of California.
We are seeing a column of policemen advancing, in full riot gear, with their batons out and shields up facing off with protesters near the steps.
"We're not leaving!" the protesters can be heard chanting.
Image source, AFPCHP policemen at the top of the image face off with pro-Palestinian protesters
Image source, ReutersPolice officers are seen clearing through and walking into the encampment
We've just seen several dozen police officers get out of coaches near to the pro-Palestinian encampment.
At least three buses carrying reinforcements appeared to have arrived at UCLA.
Image source, AFPCai Pigliucci
Reporting from UCLA
Image source, ReutersSo far this morning, we've seen footage of police breaching the perimeter on one side of the encampment - now we can see police at the ready to enter where we’re standing at UCLA.
Protesters have barricaded the encampments with plywood. You can hear hammering every so often as they try to reinforce it.
Police have warned repeatedly that protesters should leave or face arrest, but protesters continue to shout that they will not go.
Some protesters have armed themselves with makeshift riot gear including hard hats and umbrellas.
We've just seen a group of police officers withdraw from the main protest area, but now a large group is moving fast across the campus in lines.
It's unclear if the police are planning to raid the encampment but there is suddenly a lot of movement at UCLA.
Image source, AFP
Image source, ReutersWe're seeing images of some minor clashes between police officers and protesters now.
It appears there have been some skirmishes and things thrown at officers, mainly by masked protesters.
At least one person was tackled to the floor and detained by police.
We're seeing some of these images live from a helicopter camera over UCLA, so it's difficult to make out exactly what is going on.
But it appears police have stepped back from the encampment, while one protester is heard shouting "don't leave, they're coming back".
Helena Humphrey
reporting from UCLA
In the past ten minutes, what could have been either a firework or flash-bang lit up the dark early hours sky over the encampment, momentarily stunning the crowds gathered here, causing the media to scramble.
It's impossible to tell whether it came from demonstrators or gathered authorities.
But the calls by police to disperse have been ramping up in urgency and frequency - and there's the sense that between now and the early morning police could move in.
Footage from the scene also shows police officers have moved to within a few feet of a line of protesters, and appear to be speaking to some of those gathered there.
We're turning our attention back to UCLA now.
As a reminder, police have warned the pro-Palestinian demonstrators to disperse or face arrest.
However, live images from the scene show that the protesters have stayed put - and no one has been arrested yet. That could change quickly if police begin moving in.
Here's the latest aerial footage of the encampment:
Tense standoff between protesters and police at UCLA
There have been more arrests linked to pro-Palestinian protests elsewhere, this time at the University of Texas at Dallas.
Police moved in after demonstrators began setting up an encampment on a main walkway, a statement from the university said.
They were given written notice warning them to move before police moved in and tore down the encampment.
As of 17:00 local time (22:00 GMT) on Wednesday, police said 17 people had been arrested for criminal trespass.
However, CBS reported the number was actually 21, citing lawyers representing those detained.
Our reporter Helena Humphrey is outside part of the pro-Palestinian protesters' encampment, which she says could become the next flashpoint.
Here she is with the latest on the ground:
Police 'on alert' at 'unlawful' UCLA encampment
As a reminder, you can watch live footage from the UCLA campus by pressing play at the top of the page.
These are the latest photos of pro-Palestinian protesters' encampment near the the University of California Los Angeles' Royce Hall.
Protesters have blocked access to the encampment. Members of the UCLA faculty were seen standing on the frontlines after protesters were told to disperse by campus police.
Image source, Reuters
Image source, Reuters
Image source, EPA-EFE/REX/Shutterstock
Image source, ReutersCai Pigliucci
Reporting from UCLA
There’s a feeling of calm before the storm here at UCLA campus. Protesters have quietened down, with bursts of pro-Palestinian chants getting more and more infrequent.
Hundreds of people have barricaded themselves inside the encampment. Police have ordered them to leave or face arrest.
There’s been a heavy police presence for hours now, with some rows facing toward the encampments and others facing toward the streets.
Helicopters have been buzzing above. In the streets around the police, protesters hold up flags and signs protesting the war.
The Los Angeles Police Department (LAPD) and local hospitals have been put on alert. It’s not clear yet whether police will start arrests to clear out the encampment tonight - but it’s eerily quiet on the quad as we wait to see what happens next.
From East Coast to West, Pro-Palestinian protests have spread across the United States - as this video shows.
Image source, Getty ImagesSince the 7 October attack by Hamas and Israel's retaliatory assault on Gaza, students have launched rallies, sit-ins, hunger strikes and, most recently, encampments against the war.
They are demanding that their schools, many with massive endowments, financially divest from Israel.
Divestment means to sell off stock in Israeli companies, or to otherwise drop financial ties.
University endowments fund everything from research labs to scholarship funds, mostly using returns from millions - and billions - of dollars in investments.
Welcome to our live coverage of the ongoing protests on campuses in the United States.
Pro-Palestinian demonstrations have taken place at several universities - and there have been clashes with police.
The focus now is the University of California, Los Angeles (UCLA), where more than 1,000 protesters have been ordered to disperse by police.
There is a tense situation on the ground as riot police move in to clear the protest encampment.
Earlier, there was violence between pro-Palestinian groups and counter-protesters. At least 15 people were injured, according to our US partner CBS News, external.
We'll be following events live, with a team on the ground, so stay with us.