A mid-afternoon shooting on a San Francisco freeway caused a collision and left two men injured, but police are struggling to find the gunman after the victims refused to cooperate with the investigation.

According to San Francisco Police Department spokesperson Officer Albie Esparza, it was 4:30 Saturday afternoon when occupants of one vehicle shot at occupants of another vehicle while both were traveling northbound on 280 near the split to southbound 101.

Esparza says that two males in their 20s were struck in the shooting, "one in the torso/leg and the other to the neck/head area."

The suspect or suspects fled onto the southbound 101 connector following the shooting. Described only as "black males," Esparza says that "we are working on obtaining more suspect/vehicle description," but didn't have that information at publication time.

KTVU quotes eyewitnesses as saying the suspect vehicle was "an older, white sedan" and the victims' car was a "gray Mazda hatchback."

As a result of the shooting, the victims collided with another vehicle on the freeway, the Chron reports.

“When the vehicle was shot, the driver went forward and the hit the vehicle in front of him,” California Highway Patrol Officer Vu Williams told the Chron. The occupants of the other vehicle were not injured in the collision, Williams says.

The shooting victims "were already out of the vehicle, they were sitting on the side of the freeway, I don't know how much conversation they had with officers," Williams told KTVU.

"They both definitely suffered gunshot wounds," he said. They were both transported to San Francisco General Hospital, and are expected to survive.

Unfortunately, KTVU reports, "The victims are not cooperating with investigators," which makes the suspects considerably more difficult to track down. They report that the shooting is now being looked into by SFPD's gang task force.

"Bizarre, yes," SFPD Lt. Aaron Lozada told KTVU.

It's "very unusual to have this happen on a freeway...No idea what led up to these events."

Due to the uncooperative victims and lack of clear motive, Esparza is urging "anyone who witnessed this or has information on the suspect/vehicle" to contact SFPD anonymously at 415-575-4444 or to text-a-tip to TIP411 with SFPD at the start of the message.