A patrol vehicle was struck by shrapnel from an artillery round that was fired during Saturday's event at Camp Pendleton, officials said.

Marines are investigating after a 155mm artillery round exploded over Interstate 5, hitting California Highway Patrol vehicles with shrapnel.

I-5 closes 11 a.m.–3 p.m. for Marine Corps 250th anniversary live-fire demo at Camp Pendleton; expect major SoCal traffic delays.

CAMP PENDLETON — Ordnance fired over the 5 Freeway at Saturday’s 250th anniversary of the Marine Corps at Camp Pendleton prematurely detonated, striking and damaging a California Highway Patrol vehicle that was part of Vice President JD Vance’s detail, the CHP said Sunday.

An artillery round fired over Interstate 5 at Sunday’s live-fire demonstration at Camp Pendleton prematurely detonated, striking and damaging a California Highway Patrol vehicle that was part of Vice President JD Vance’s detail, the CHP said Sunday.

California closed part of Interstate 5 on Saturday after military officials confirmed artillery would be shot over the freeway. Then it reopened temporarily.

The mishap, during an anniversary celebration for the Marine Corps attended by the vice president and defense secretary, underscores safety concerns that Gov. Gavin Newsom voiced before Saturday’s event at Camp Pendleton.

The Marines are gearing up for their 250th birthday Saturday with a high-octane amphibious demonstration at Camp Pendleton's Red Beach, featuring amphibious vehicles storming the