(CN) - At least 20 people were arrested outside a Donald Trump rally in Costa Mesa, California, Thursday night after protestors and supporters of the GOP front-runner clashed in a running, three-hour battle.
Trump's rally at the Pacific Amphitheatre went off with nary a hitch and only a smattering of cat-calls from protestors.
However, after Trump left for Burlington, California, for the state's Republican convention, a running conflict broke out in the street and went on for hours.
According to the Orange County Sheriff's Department, one Trump supporter had his face bloodied in a scuffle as he tried to leave the arena.
Another man jumped on a police car, smashing in its front and rear windows.
According to published reports, tensions began prior to the event when several anti-Trump protesters, some of them waving Mexican flags, taunted those waiting in line to go inside.
A short time later, several topless woman arrived in the square outside the theater, their breasts covered by campaign stickers supporting Sen. Bernie Sanders.
Police in riot gear and on horseback eventually dispersed the crowd after the rally ended, and the police department said no major injuries were reported.
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.