A man with a shotgun, loaded handgun, ammunition and several fake passports in his vehicle was arrested at a security checkpoint outside Donald Trump’s rally in California.

The 49-year-old Las Vegas resident was driving an unregistered black SUV with a “homemade” licence plate that was stopped by deputies assigned to Saturday night’s rally in Coachella, east of Los Angeles.

The driver claimed to be a journalist but it was unclear if he had the proper credentials, Riverside County Sheriff Chad Bianco told reporters.

Deputies noticed the interior of the vehicle was “in disarray” and a search uncovered the weapons and ammunition, along with multiple passports and driver’s licences with different names, Bianco said. 

The man was arrested on suspicion of possessing a loaded firearm and possession of a high-capacity magazine, a statement from the sheriff’s department said.

“This incident did not impact the safety of former president Trump or attendees of the event,” the department said. 

Trump had not yet arrived at the rally at the time of the arrest. 

The man was released the same day on $US5000 ($A7400) bail and is scheduled to appear in court on January 2.

Bianco declined to speculate about the suspect’s motives or frame of mind. 

“We know we prevented something bad from happening, and it was irrelevant what that bad was going to be,” Bianco said.

The man made it past an outer security boundary and was stopped at an inner perimeter patrolled by the sheriff’s department, Bianco said. 

Another security checkpoint closer to the rally site was operated by the Secret Service. 

“The US Secret Service assesses that the incident did not impact protective operations and former president Trump was not in any danger,” the US attorney’s office said in a statement. 

“While no federal arrest has been made at this time, the investigation is ongoing.”

Media members, as well as VIP ticket holders, were routed through a number of intersections manned by state and local law enforcement officers before arriving at a large, grassy area where drivers were asked to open hoods and trunks, and each vehicle was searched. 

Other general ticket holders were directed to a site roughly 5km away from the rally, where they were boarded onto buses and driven to the site.

Trump’s campaign did not immediately respond to a request for comment on the arrest.

Security is tight at Trump rallies following two recent assassination attempts. 

In September, a man was indicted on an attempted assassination charge after authorities said he staked out the former president for 12 hours and wrote of his desire to kill him. 

The man was discovered hiding with a rifle near Trump’s Palm Beach golf course.

That arrest came two months after Trump was shot and wounded in the ear in a July assassination attempt during a campaign rally in Pennsylvania.

With Reuters