DENVER -- A car that reportedly ran a red light plowed into four motorcycles Tuesday afternoon, injuring all the riders.

The accident occurred just before 4 p.m. at 8th Avenue and Speer Boulevard, just in front of Denver Health.

The motorcycle riders have been taken to the hospital. The extent of their injuries is not known but police said some of the riders were in serious condition when they were taken away. One victim has been taken into surgery.

Pieces of all four Harley Davidson motorcycles were scattered all over Speer Boulevard. Police shut down 8th Avenue for more than two hours to conduct their investigation, causing a major backup in downtown Denver during the evening commute.

Jeff Thomas said he was riding with the group when he got caught behind at a red light. Just as he was about to catch up to his friends, he saw the crash occur in front of him. Thomas said that the motorcycle riders were going northbound on Speer Boulevard when a black Lexus went through the intersection, striking all four bikes at once.

"I thank God that they're all alive. From what I've seen of that, I don't know if I'll ever ride again ... It was pretty nasty. It really was," said Thomas.

Thomas said that the motorcycle riders had the green light.

"The intersection was clear, they came through 8th Avenue and this black car here in the intersection just came out of nowhere, by itself, and ran right in front of the bikes and they all collided with the car," Thomas said.

Police are investigating the case.

It is not known what charges the driver may face.