Attack on U.C.L.A. Encampment Stirs Fears of Clashes Elsewhere

The first big pro-Israel counter demonstration was on Sunday in Los Angeles, home to large Israeli and Jewish populations. More are planned in the coming days.

At a rally at the University of California, Los Angeles, last Sunday, Elan Carr, the leader of an Israeli diaspora group, told more than 1,000 demonstrators that Jewish mobilization at universities was beginning.

“We will take back our streets. We will take back our campuses from Columbia University to U.C.L.A. and everywhere in between,” Mr. Carr, chief executive of the group, the Israeli American Council, told the crowd.

The U.S. and Israeli national anthems were sung, and there were prayers, speeches by Jewish leaders and Israeli pop songs. But close to the rally, hundreds of pro-Israel and pro-Palestinian protesters faced off, shouting insults and threats. Fights broke out after a barrier that the university had erected to separate the two sides was breached.

It was a volatile start to what would become one of the most violent stretches of campus unrest. Days later, scores of counter demonstrators stormed the pro-Palestinian encampment at U.C.L.A. and clashed late Tuesday night into early Wednesday morning.

In an interview, Mr. Carr said the Israeli American Council, which describes itself as a nonpartisan group representing Israelis and Israeli Americans, did not condone the violence. But the nonprofit organization’s plans to stage more counter-protests on or near other college campuses has raised the prospect of further confrontations between pro-Israel and pro-Palestinian factions.

“The fear I have is that this is a combustible situation aggravated by agitators who seem intent on escalating the level of violence against the other side,” said David Myers, a U.C.L.A. professor of Jewish history who, with colleagues, tried to act as a buffer between the two sides. “This could spread like a contagion.”