SAN DIEGO  (NewsNation Now) — Supporters of President Donald Trump clashed with counter-protesters in San Diego on Saturday, prompting police to declare the gathering an unlawful assembly because of acts of violence.

Officers were hit with rocks, bottles and eggs, police said, and the crowd directed pepper spray at them.

In one instance, a line of counter-protesters advanced on a smaller group of people from the Patriot March, shouting and telling them to leave. One member of the group, who was dressed in all black with their face covered, pulled out a can of chemicals and sprayed it in the Trump supporters’ faces.

At other times, members of the two groups shoved, swung and threw items at each other along the boardwalk. The scuffles drew a heavy police presence, with teams of bicycle officers moving in to separate the demonstrators and asking bystanders to clear out.

Some of the counter-protesters waved flags declaring themselves anti-fascists, or antifa, an umbrella term for a loose collection of far-left militant groups that confront demonstrators for neo-Nazi groups and right-wing causes.

The violence in San Diego mirrored unrest around the nation in the wake of a violent riot at the U.S. Capitol Wednesday, where a pro-Trump mob breached congressional security and interrupted the process of certifying President-elect Joe Biden’s victory. Five people, including a San Diego woman who was among the rioters trying to enter the Capitol, died.

Lawmakers and other public figures have called for Trump to step down or be removed from office in the wake of the violence, blaming him for inciting the riot by organizing a large rally in Washington and for claiming, without evidence, that the election had been rigged against him.

NewsNation affiliate KSWB and The Associated Press contributed to this report.