LOS ANGELES — Pro-Palestinian and pro-Israel protesters have clashed at the University of California, Los Angeles (UCLA) as demonstrations over the war in Gaza continue across US campuses.

Nationwide rallies — during which there have been hundreds of arrests — showed no sign of stopping over the weekend.

At UCLA "physical altercations broke out" after a barrier separating the two sides was breached, an official said.

The White House has insisted that demonstrations must remain peaceful.

The US government respected the right of protesters demonstrating over the Israel-Gaza war, a National Security Council spokesman told ABC.

But it repeated its condemnation of antisemitic incidents that have been reported, as well as "all the hate speech and the threats of violence out there", John Kirby told ABC on Sunday.

At UCLA, a pro-Palestinian encampment has grown in size in recent days, as has a group of pro-Israeli counter-protesters.

The Israeli American Council (IAC) organized the counter-protest. It recently said it had "profound concern" over the antisemitism reported elsewhere, including at Columbia University.

Many pro-Palestinian protesters have sought to distance themselves from antisemitic incidents and in some cases they have blamed outside agitators.

The two groups at UCLA remained peaceful until Sunday, Reuters news agency reported, when campus police with batons separated them as they pushed and shoved each other, and traded punches.

It was not immediately clear which group broke through the barrier that separated them.

"We are heartbroken about the violence that broke out," the university said, adding that additional security measures had been introduced in response.

Tensions flared at US universities after the 7 October Hamas attack, in which about 1,200 people were killed in Israel, and the retaliatory Israeli military assault that has killed more than 34,000 people in Gaza.

In the last fortnight, a nationwide uprising has emerged which university officials and law enforcement have struggled to contain. They have blamed outside groups for infiltrating the demos.

The movement seems to have been emboldened by the arrest of more than 100 protesters at Columbia University in New York City after police were called to clear an encampment.

Hundreds of people have since been arrested in locations across the US from coast to coast - many of whom had pitched their own tents on university grounds.

Protesters are demanding a ceasefire in the conflict, and that their universities - many with massive endowments - cut their financial ties, or divest, from Israel.

They say that companies doing business in or with the nation of Israel are complicit in its ongoing war on Gaza - and so are the institutions that invest in those companies.

Officials have also scrambled to tackle alleged incidents of antisemitism, with a number of Jewish students voicing fears for their safety.

At several campuses, they have spoken of incidents ranging from chants and signs supporting Hamas - a proscribed terror group in the US - to physical altercations and perceived threats.

Northeastern University in Boston, Massachusetts, reported "virulent antisemitic slurs" in a statement on Saturday that accused "professional organisers with no affiliation to Northeastern" of infiltrating a student protest.

More than 100 people were detained, it added.

In other recent developments:

Among hundreds of other activists arrested over the weekend was Green Party presidential candidate Jill Stein, who was detained with about 80 others at Washington University in St Louis, Missouri

Protesters at Yale University set up a new encampment after a previous one was cleared by police, the student newspaper reported

California State Polytechnic University has become the latest institution to request that students switch to virtual classes — BBC