US Marines probe firing of live artillery over California highway

One shell exploded in mid-flight, showering nearby police vehicles with shrapnel

A general view of a live-fire exercise as US Vice President JD Vance and second lady Usha Vance (not pictured) attend the 250th anniversary celebration of the United States Marine Corps at Camp Pendleton, California, US, Oct 18, 2025. The event, titled "From Sea to Shore: A Review of Amphibious Strength", features a live amphibious assault demonstration and honored the Corps’ legacy of service and readiness. REUTERS

The US Marines are investigating the firing of live artillery over a major California highway during a ceremony attended by Vice President JD Vance in which one shell blew up in the air and rained shrapnel onto police vehicles parked nearby, officials said on Monday.

Nobody was injured in the mishap, which occurred on Saturday afternoon during a demonstration of the military's M777 Howitzer heavy artillery pieces at a Camp Pendleton event celebrating the 250th anniversary of the US Marine Corps.

But the incident along Interstate 5, about 40 miles (64 km) north of San Diego, drew sharp criticism from California Governor Gavin Newsom, who blamed the Trump administration for what he called a "reckless" and "profoundly absurd show of force."

The California Highway Patrol's border division chief, Tony Coronado, a Marine veteran, labeled the mishap "an unusual and concerning situation," adding "it is highly uncommon for any live-fire or explosive training activity to occur over an active freeway."

The Highway Patrol had temporarily closed down a 17-mile stretch of the I-5 freeway to traffic as a precaution in advance of the M777 exercise.

But a CHP patrol cruiser and a motorcycle that had been assigned to Vance's security detail for his arrival and were parked at a freeway on-ramp near the base during the event were showered by metal shrapnel when the first of 60 artillery shells that the Marines had planned to shoot over the freeway prematurely exploded in flight, according to a CHP incident report shared with Reuters.

A 2-inch-wide chunk of shrapnel dented the patrol car's hood, and smaller pieces rained onto and around a motorcycle, but no serious damage was detected, the report said.

"After the failed round, the exercise was terminated and no additional rounds were fired," the report said.

Camp Pendleton did not immediately respond to a request for comment.

The relatively brief closure of the I-5, which connects the Los Angeles area with San Diego County, caused traffic gridlock across the region, the Los Angeles Times reported.

The White House said on X "the Marines repeatedly said there are no public safety concerns with today's exercises."

A US official familiar with the situation said an investigation was under way and Saturday's aborted Howitzer demonstration followed a "test" firing of 30 155-millimeter artillery shells the day before, though it was not made clear whether Friday's rounds were shot over the freeway. The Los Angeles Times reported some were.

The official said safety measures were in place on Saturday, and that when an artillery spotter noticed that one shell did not land where it was supposed to, a "cease-fire was called."