The arrest in the seaside Los Angeles suburb of Santa Monica came just hours after 50 people were shot dead at a gay nightclub in Orlando, Florida.

Police sources said there was no known connection between the arrest in Santa Monica and the attack in Orlando, Florida - which has since been confirmed as the worst mass shooting in US history.

Participants at the gay Pride event in Los Angeles honored those who died in Orlando

Santa Monica police chief Jacqueline Seabrooks said that a 20-year-old male was caught with multiple assault rifles, high-capacity magazines and ammunition, as well as some bomb-making materials in his car, which had Indiana license plates.

Locals had reported suspicious behavior on the street earlier where he was parked with his white Acura-brand sedan facing in the wrong direction.

The suspect apparently told police officers after his arrest that he had wanted "to harm (the) Gay Pride event" - in reference to the annual parade that took place in Hollywood on Sunday amid heightened security.

A support network

Authorities said they had considered calling off the parade in Los Angeles after the events in Florida but then decided to go forward while increasing security. The march went ahead without incident. Thousands of people marched, joined in grief, through the streets of Los Angeles for the Gay Pride parade.

Participant Marpa Franzoni, 28, told the AFP news agency that she "won't be silenced and we won't be curtailed no matter what kind of aggression they throw at us."

"I'm in shock. It's more important than ever to show our visibility and support for our community," Franzoni added.

ss/jm (AFP, AP)