Five people were killed and six injured Saturday in a head-on collision involving seven motorcyclists and one car on a rural highway a few miles north of the Mexican border, according to the California Highway Patrol.

Authorities are looking for the driver of a second car that is believed to have triggered the crash and then left the scene.

Four of the dead belonged to a Lakeside motorcycle club called the Saddle Tramps, according to CHP Officer Deeann Goudie. Goudie said the club was celebrating its 10th anniversary Saturday with a ride across the desert.

The members met at 9 a.m. for breakfast in Lakeside before getting on the road, Goudie said. They were riding east on Route 98 near Ocotillo, about 80 miles out of San Diego, when a gold Honda Accord revved up behind them and tried to pass.

A white Dodge Avenger coming from the opposite direction swerved to avoid the oncoming Honda, lost control and then crashed into the pack of motorcycles.

Four motorcyclists -- including one husband-and-wife team who were riding the same bike -- were killed, Goudie said. The passenger of the Avenger was also killed.

Goudie said several of the people who were injured were airlifted to hospitals.

The gold Honda that tried to pass the motorcycles did not suffer any damage and sped off, Goudie said. She said authorities did not know the year of the car or the license plate number. Witnesses said the driver was a man wearing a baseball cap.

-- Kate Linthicum