There was a CHP-involved shooting Wednesday afternoon on I-280 in San Francisco, near the Mariposa Street on-ramp, and all southbound lanes of the freeway were subsequently closed.

The shooting, which occurred on I-280 in the southbound lanes south of Mariposa Street, came after an apparent struggle between a CHP officer and a pedestrian who was possibly armed, around 4:30 pm Wednesday.

KTVU reports, via the CHP, that a knife was found at the scene that belonged to the pedestrian. The exact nature of the struggle, or how it unfolded, has not been made public.

According to KPIX, there were two vehicles by the side of the road at the time of the shooting, and there may have been some sort of collision that preceded the incident.

California Highway Patrol sent out a Sig Alert about the situation at 4:53 pm. All southbound lanes of I-280 were blocked due to the investigation.

Those lanes did not reopen until around 9 pm.

The pedestrian was reportedly hospitalized with non-life-threatening injuries, and is expected to survive.

We'll update you as we learn more.

This story has been updated throughout.