A controversial plan to fire live artillery shells across a major Southern California highway during a military event attended by Vice President JD Vance has sparked significant opposition from Governor Gavin Newsom. Citing safety concerns, Newsom ordered the closure of a 17-mile (27-kilometer) stretch of the interstate.

“The President is prioritizing ego over responsibility by neglecting public safety,” Governor Newsom, a Democrat, stated. “Shooting live rounds over a busy highway is not only inappropriate but also hazardous.”

Vice President Vance and officials from the U.S. Marine Corps at Camp Pendleton have asserted that the artillery exercise poses no safety risks and that traffic disruption on Interstate 5, the principal coastal route between San Diego and Los Angeles, is unnecessary.

The vice president, a Republican, along with Defense Secretary Pete Hegseth, is visiting Camp Pendleton in North San Diego County to commemorate the Marine Corps’ 250th anniversary. The anniversary celebration will feature demonstrations of amphibious vehicles and aircraft, culminating in a beach landing.

While state authorities had initially considered closing the freeway earlier in the week, the U.S. Marines assured on Thursday that the event would be conducted within approved training areas and in accordance with established safety guidelines.

State transportation officials ultimately made the decision to close the freeway after practice firings over the freeway Friday evening and a request from event organizers for signage along the road stating “Overhead fire in progress.”

California Highway Patrol said a stretch of the highway would be closed Saturday from 11 a.m. to 3 p.m. local time, although travelers should expect delays before, during and after the event.

“This is all because of the White House-directed military event, that for the safety of the public, we need to shut down the freeway since they’re sending live ordinances over the freeway,” California Department of Transportation spokesperson Matt Rocco said.

The Associated Press has reached out to Vance’s office and the U.S. Marines for comment.

In a statement to The New York Times, a spokesperson for Vance, William Martin, said Newsom is misleading the public about the safety risk. He said it was routine training.

“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,” Martin said.

Rocco said the I-5 closure could cost up to another two hours of trip time for those commuting between San Diego and Los Angeles. The freeway carries with 80,000 travelers and $94 million in freight through the corridor daily, according to the governor’s office. Passenger rail services running parallel to the I-5 have also been canceled for the afternoon.