Hundreds of rowdy protesters have broken through barricades and thrown eggs at police outside a hotel where Donald Trump addressed California’s Republican convention.

Police officers block traffic after protesters stormed the streets. AP

Several Trump supporters said they were roughed up but no serious injuries were reported.

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The protest just outside San Francisco occurred a day after anti-Trump protesters took to the streets in Southern California, blocking traffic and damaging five police cars in Costa Mesa following a speech by Trump.

Demonstrators at both locations waved Mexican flags, an action meant to counter the Republican frontrunner’s hard stance on immigration and disparaging remarks about Mexico.

Because of the protest, Trump was rerouted to a back entrance on Friday. In a surreal scene, news helicopters showed the billionaire businessman and his security detail walking between two concrete freeway barriers before hopping down onto a grass verge and walking across a service road.

“That was not the easiest entrance I ever made,” Trump quipped when he started speaking to the convention delegates. “It felt like I was crossing the border.”

A man selling eggs to throw at a cut-out of US Republican Presidential candidate Trump. EPA.

Outside, crowds of anti-Trump demonstrators broke through steel barricades and pelted riot police with eggs as the officers stood shoulder-to-shoulder to keep the demonstrators from entering the hotel.

A man wearing a red hat bearing the Trump campaign slogan “Make America Great Again” was punched in the head from behind while being jostled by a group of shouting protesters.

Another Trump supporter said he was punched and spit upon by demonstrators who also threw his phone to the ground.

“It went gangbusters. They attacked me,” said Chris Conway, a mortgage broker from San Mateo.

Burlingame is right outside San Francisco, a progressive bastion that became the focal point of the immigration debate last year when an immigrant in the country illegally, and who had been deported multiple times, shot and killed a woman walking with her father.

Immigration has been one of Trump’s main issues and he often has highlighted the San Francisco killing while touting his plan to build a wall along the entire Mexican border.

California’s primary is June 7, a date once seen as too late to influence the selection process. Now it is seen as the election that either gets Trump over the threshold needed for the nomination or leaves him just short.