At least three people were killed and six others were injured after a vehicle veered onto a sidewalk in a tunnel in downtown San Diego.

The San Diego Fire-Rescue Department said first-responders were dispatched at 1400 block of B Street at 9:05 a.m., in a tunnel near San Diego City College.

“Our crews found, obviously, a tragic incident under the bridge,” San Diego Fire Department Chief Colin Stowell said in a news briefing.

The 71-year-old driver of a Volvo station wagon has been detained and being investigated for driving while impaired.

Police Chief David Nisleit clarified that the suspect was cooperative and did not attempt to leave the area, but instead attempted to render aid and identified himself to officers on the scene.

Three people had died on the scene while five others were taken to the hospital, in which two are in critical condition.

According to Nisleit, it was unclear whether the victims were homeless, as several tents and belongings were set up inside the tunnel.

“I don’t know if people were sleeping, if people were sitting there,” Nisleit said during the briefing.

“I have not been given that exact (information).”

Minutes before the crash, police received a radio call about a vehicle matching the description of the Volvo, but officers did not have visibility at the time.

“For whatever reason, it veered to the right and went completely up onto the sidewalk,” he said.

“The way he was driving down the sidewalk, it was like he didn’t take his foot off the gas until he got to the other side of the street,” said witness Ronnie Williams.

He added that the driver got out of the vehicle and “casually walked away” from the scene.

Michael Luke, another witness, said that the driver stayed at the scene looking distraught.

“I saw the wagon move over and things just started popping up .. and the dragging … Horrific,” he said.