LOS ANGELES — Federal authorities said on Monday that they had thwarted a domestic terror plot by an American military veteran aimed at “multiple targets” in Southern California, including Huntington Beach, the port of Long Beach and the Santa Monica Pier.

The suspect, who was identified as Mark Steven Domingo, was seeking retribution for the recent attacks on mosques in New Zealand, according to the authorities. He spoke of unleashing an attack similar to the massacre in Las Vegas, aiming to kill hundreds of people, and was especially targeting white nationalists, Jews, churches and military bases, according to court documents filed Monday.

The suspect was arrested Friday night after he received what he thought was a live bomb, but in fact was an inert explosive device that was delivered by an undercover law enforcement officer as part of an investigation by the F.B.I.’s Joint Terrorism Task Force.

After Mr. Domingo was given the inert device, he purchased “several hundred” nails that he wanted to put inside the bomb, Nicola Hanna, the United States attorney for the Central District of California, said at a news conference on Monday.