Navy officials on Friday released the names of two sailors killed in a predawn traffic pileup on southbound Interstate 5 near Camp Pendleton.

The name of a third motorcyclist killed in the Thursday morning crash has not been released.

The two sailors were identified as Jess Davis, 38, of Tennessee, and Stephen Williams, 37, of Texas. Davis served aboard the Point Loma-based attack submarine USS Alexandria, and Williams was assigned to Southwest Regional Maintenance Center in San Diego, Navy spokesman Brian O’Rourke said.

They and the third victim were part of a group of four motorcyclists who crashed into a freeway pileup near Las Pulgas Road about 3 a.m.

The initial crash occurred when a Jeep Wrangler slammed into a guardrail before colliding with a Mercedes-Benz Sprinter van. The van overturned. The motorcyclists slammed into one or both of the disabled vehicles.

Williams, Davis and a third rider died at the scene.

Paramedics took the fourth motorcyclist to a hospital for treatment of serious injuries.

Four other people suffered injuries, the CHP reported. Two men in the Jeep — the 29-year-old driver and a 50-year-old passenger — suffered life-threatening injuries and were flown to a hospital. Two people in the Mercedes also were hospitalized, the CHP reported.

Union-Tribune staff writer Teri Figueroa contributed to this report.