A pedestrian was struck and killed by a big-rig at Oak Street and Octavia Boulevard on Thursday.

The horrific accident occurred shortly after 6:30 a.m., according to media reports.

The big-rig, hauling a trailer carrying cars, either struck or nearly struck a UCSF van filled with doctors before hitting the pedestrian, according to a witness. As of 7:15 a.m., the pedestrian remained stuck under the big-rig and emergency responders were on the scene trying to extricate the body. The person killed is believed to be a man.

KTVU reported seeing a second person being put into an ambulance.

Commuters are advised to avoid the area. Oak Street from Laguna to Gough streets is closed as is Octavia Boulevard from Page to Fell streets. Traffic on Highway 101 is backed up from the Octavia Boulevard exit ramp into San Francisco.

The Octavia Boulevard off-ramp is notorious for traffic accidents, both near and at the Market Street intersection.