A suspected New Year's Eve terror plot by an extremist group has been foiled by federal authorities in Los Angeles, officials say. 

Four alleged members of the Turtle Island Liberation Front - an offshoot of a pro-Palestinian anti-government group - have been arrested on suspicion of planning a coordinated bombing attack in at least five locations across southern California, the FBI and LA law enforcement said on Monday.

The suspects were apprehended last week while traveling to the desert east of Los Angeles to test improvised explosive devices, officials said.

The FBI believes it has "disrupted the plot", but an investigation to identify other potential suspects is ongoing.

US Attorney General Pam Bondi said on X on Sunday that the agencies prevented "far-left" extremists from executing "a massive and horrific terror plot".

Audrey Illeene Carroll, 30; Zachary Aaron Page, 32; Dante Gaffield, 24; and Tina Lai, 41, face charges including conspiracy and possession of an unregistered destructive device, according to the complaint filed in the US District Court for the Central District of California. 

On 12 December, the group travelled to the desert with "precursor chemicals" and were allegedly going to create bombs with their wares, officials said during a media conference on Monday.

A surveillance plane captured footage of their movements and the Los Angeles FBI SWAT team, along with the FBI, moved in and arrested the quartet without incident. 

The bombing plot involved explosive devices being planted at locations that targeted two US companies described as logistic centres at midnight on New Year's Eve in the Los Angeles area. 

The group also allegedly discussed attacking Immigration and Customs Enforcement agents and vehicles with pipe bombs in January or February, according to the complaint said. 

Carroll allegedly said: "That would take some of them out and scare the rest of them."

"The successful disruption of this plot is a powerful testament to the strength of our unified response," said LAPD Chief Jim McDonnell, adding that work through allied agencies "prevented a potential tragedy and reaffirmed our shared commitment to safeguarding our communities".