Several protesters gathered outside Republican presidential candidate Donald Trump’s rally at Orange County fairgrounds in Costa Mesa, California, amid reports that the crowd grew violent. Costa Mesa police had reportedly created a line separating supporters from protesters but, according to a Los Angeles Times reporter, the Sheriff’s department and the police were losing control of the crowd.

The LA Times reported a face-off between the protesters and supporters while Trump, addressing the rally, said: “The safest place in the country to be is at a Trump rally.”

The LA Times report also added that some protesters were throwing debris at passing cars, while others waved anti-Trump signs and played loud music. Footage showed a protester throwing debris at a passing pickup truck while one group carried benches and blocked the entrance to the 55 Freeway along the Newport Boulevard. Some even tossed rocks at motorists on the ramp. One demonstrator was seen stomping on a police cruiser, whose windows were smashed.

Traffic in the area was halted as several people walked on the roadway, carrying anti-Trump placards, and American and Mexican flags.

The signs reportedly included slogans like “Hate won't make us great again,” and “Make America great, stop the hate.” Some of the protesters were draped in Mexican flags, opposing Trump’s call to build a massive wall on the southern border and make Mexico pay for it.

“We’re going to have to get a lot tougher than we are because we have problems,” Trump said, according to the LA Times, in his first appearance in California since it became clear that the state’s primary on June 7 will be crucial to determine if he can win the delegates needed to get the GOP nomination.

Police officials from the Costa Mesa Police Department were seen in riot gear, lined up across a roadway, asking protesters to clear the out.

Genevieve Huizar, 60, of Santa Ana, carried a sign that read, "Say it loud, say it proud, no to Trump” and told LA Times: “They use Mexican people as labor and send them overseas to wars,” adding: “We are people.”

While the doors to the event opened at 4 p.m., people had started to queue before 10 a.m. Officials used metal detectors while a report by KABC network said that the U.S. Secret Service was also helping to keep security tight.