A helicopter that provided air medical services crashed on a freeway in Sacramento, California, on Monday evening, leaving several people injured, CBS News reported.

"There has been a harrowing helicopter crash on 50 eastbound west of 59th St.," Sacramento Mayor Kevin McCarty said on X, thanking first responders at the Sacramento Fire Department.

Survivors are being treated at local hospitals, McCarty said.

At least three people suffered critical injuries, according to CBS News.

The crash happened just after 7 pm, according to Officer Mike Carrillo, a spokesperson for the Valley Division of California Highway Patrol.

In images posted online, a long line of cars on Highway 50 could be seen backed up just behind a crashed helicopter. Information about the number of people on board or injuries was not immediately available.

Carrillo said residents should expect delays on the highway and use alternate routes. “We ask the public to avoid the area and allow emergency crews to work safely,” he added.

The cause of the accident is still being investigated.