Under mounting political pressure, US President Joe Biden broke his silence on campus unrest over the war in Gaza on Thursday, saying Americans have the right to demonstrate but not to unleash violence.

"There is a right to protest, but not a right to cause chaos," Biden said in remarks at the White House.

With television images of campus unrest that have swept the country in recent days playing out on news networks, Biden has faced criticism of his handling of the situation. He had been leaving it largely up to his spokespersons to comment.

The Democratic president, seeking re-election in November, has walked a careful line of denouncing antisemitism while supporting young Americans' right to protest and trying to limit longer-term political damage.

Biden said both sides had a point, that peaceful dissent was critical to a democracy but that violence would not be tolerated.

"Destroying property is not a peaceful protest. 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," he said.

Biden said the United States was not an authoritarian nation that silences critics but that "order must prevail."

"Dissent is essential to democracy but dissent must never lead to disorder or denying the rights of others so students can't finish the semester and college education," he said.

Biden, asked whether state governors should call in National Guard troops to restore order if necessary, replied "no."

In response to a reporter's question, Biden said the campus protests had not forced him to reconsider his policies in the Middle East.

Student protesters are calling for an immediate ceasefire in Gaza and demanding schools divest from companies that support Israel's government.