Four people were injured Friday in a collision that closed traffic on Kingsbury Grade for at least an hour.

The collision reportedly occurred about 2:45 p.m. near the top of the grade.

The victims sustained “serious” injuries, according to Nevada Highway Patrol deputy Dan Lopez. Two people were flown to Renown Health Regional Medical Center in Reno and two were transported by ambulance.

The condition of the victims was unknown as of press time. The highway was closed for at least an hour, but at 4:15 p.m. one eastbound lane was open, Lopez said.

“There was a black Toyota Yaris driving westbound on 207 toward the lake, and that had three females in the vehicle, and we’re not sure of ages at this time,” Lopez said. “A white Subaru was going eastbound with one adult female, and the black Toyota crossed over and hit the Subaru.”

Lopez said he was not sure if it was a head-on collision or not. He also said there’s no suspicion of alcohol being related to the incident at this time.

“We’re still investigating for a little bit longer,” Lopez said about 3:30 p.m. Friday. “It’s definitely serious injuries on all of them.”

At that time, Lopez said the incident was caused by unknown reasons.

Traffic on Kingsbury Grade was moving but very slow as law enforcement officials investigated the scene and had the cars towed, Lopez said. No updates were available by press time.