All northbound Interstate 5 and 805 traffic at the merge is being detoured to the state Route 56 (SR-56) bypass lanes due to police activity, according to the California Department of Transportation (Caltrans).
All traffic is being detoured to eastbound SR-56. Motorists are advised to avoid the area if possible.
As of Monday at 3:30 p.m., it was not known how long the freeways will be closed.
One person was wounded Monday when at least one gunman in a moving car opened fire on vehicles — including an ambulance and a California Highway Patrol cruiser — in four locations on Interstate 805 and I-5, authorities reported.
The seemingly random drive-by gunfire began about 10:30 a.m., starting on northbound I-805 near East Plaza Boulevard in National City, according to San Diego police. At least one bullet hit a car in that assault, though no one was injured.
A short time later, a shooting on I-805 at Mesa College Drive injured a 26-year-old man, SDPD Lt. Darryl Hoover told reporters. Medics took him to a hospital for treatment of a non-life-threatening leg wound.
Within the next 15 or so minutes, gunfire again erupted on I-805 near state Route 163, where a CHP officer was assisting a motorist, and on northbound I-5 in the area of Del Mar Heights Road, according to Hoover. An ambulance apparently was targeted in the latter shooting, he said. No one was injured in those attacks.
All of the gunfire may have come from a white 2005 or 2006 Chevrolet Malibu, California license plate number 5POM917, police said. That sedan, carrying at least two men, had been involved in a hit-and-run collision on East San Ysidro Boulevard shortly before the shooting spree began, and it matched descriptions of the car involved in the firearm assaults, the lieutenant said.
The suspect vehicle is registered to a Lancaster resident, according to police.
In the early afternoon, CHP shut down a roughly three-mile stretch of I-805, between I-8 and Mesa College Drive, so investigators could search the roadway for bullet casings and other evidence. It was unclear how long the closure would last, a CHP spokesman said.