Gavin Newsom slammed Donald Trump's plans to fire artillery shells over a California highway as part of a military demonstration to celebrate the Marine Corps' 250th anniversary. 

The California Governor branded the plan 'profoundly absurd' and said it was a 'show of force that could put Californians directly in harm's way.' 

Newsom shut down a 17-mile stretch of Interstate 5 between Los Angeles and San Diego in response to the move, which caused mass gridlock on the highway on Saturday. 

Although the Trump administration said the artillery fire was to mark the Marine Corps' anniversary, Newsom said it was no accident that it also fell on the same day anti-Trump 'No Kings' protests were held. 

'Using our military to intimidate people you disagree with isn't strength — it's reckless, it's disrespectful, and it's beneath the office the president holds,' Newsom told the New York Times. 

Newsom - a possible contender for the Democratic presidential nomination in 2028 - also took to X to slate the plans, accusing Trump of failing to safely coordinate the artillery fire with California officials. 

'It is not safe for people to drive on a major freeway at high speeds directly under LIVE MUNITIONS,' his office wrote. 

'White House not communicating, endangering the public, and then trying to blame the Governor for doing the right thing — keeping people out of harm's way — yet another day living in Trump's authoritarian America.' 

Despite Newsom's hand-wringing over Trump's military spectacle, the White House insisted on Saturday that the artillery fire from Camp Pendleton was safe. 

'Gavin Newsom wants people to think this exercise is dangerous,' William Martin, the communications director for Vice President JD Vance, said in a statement. 

'The Marine Corps says it's an established and safe practice. Newsom wants people to think this is an absurd show of force. The Marine Corps says it's part of routine training at Camp Pendleton.

'If Gavin Newsom wants to oppose the training exercises that ensure our Armed Forces are the deadliest and most lethal fighting force in the world, then he can go right ahead.'