SAN LEANDRO -- An Oakland man was killed Wednesday afternoon when his truck slammed into a tree in San Leandro's Marina neighborhood.

The wreck took place just before 4:45 p.m. on Monarch Bay Drive near Fairway Drive, Lt. Mike Sobek said.

Police say the victim was driving north on Monarch Bay Drive in a silver 2005 Chevy Silverado pickup when he lost control of the vehicle and twice drove over an island divider. The truck then hopped a curve, slammed into a tree and flipped on its side.

Witnesses at the scene flipped the truck over and pulled the man out and attempted to perform CPR, but emergency crews pronounced him dead at the scene.

The name of the 62-year-old victim was being withheld until authorities can reach his family, an Alameda County coroner's spokesman said Thursday.

A preliminary investigation revealed the victim may have had some type of medical issue before he crashed. Autopsy and toxicology reports are pending, police said.

Alcohol doesn't appear to be a factor in the crash, Sobek said.

Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.