FREMONT -- A 76-year-old Brentwood man was killed Saturday in an early-morning crash on northbound Interstate 680, authorities said.

His identity was not immediately released because the man's family had not yet been notified, an Alameda County Coroner's office spokesman.

No other injuries were reported.

The collision happened shortly after 1 a.m. and blocked three lanes of northbound I-680 between Vargas and Sheridan roads, said a California Highway Patrol spokesman. The lanes were blocked until 3:30 a.m.

The cause of the collision remained under investigation on Saturday.

Contact Kristin J. Bender at kbender@bayareanewsgroup.com. Follow her at Twitter.com/kjbender.