Tensions flare at Donald Trump rally in Orange County

COSTA MESA, Calif. (KABC) -- Crowds grew bigger by the minute outside a Donald Trump rally being held at the Orange County Fairgrounds in Costa Mesa on Thursday.

Thousands of Trump supporters entering the fairgrounds were met by several protesters.

Officials with the Costa Mesa Police Department and Orange County Sheriff's Department created a line separating the supporters and protesters.

Several officers were mounted on horseback or dressed in riot gear.

Items being thrown from the protesters toward the supporters were captured on video from Air7 HD. Intense shouting matches were also witnessed.

Doors to the event opened at 4 p.m., but the line began forming before 10 a.m.

Security for the event was tight, with officials using metal detectors on all those attending. The U.S. Secret Service was also on hand.