An infant is dead and a young child is injured after being found on a freeway in Los Angeles County, California, according to reports.

California Highway Patrol responded to the scene around 4:30 a.m. on Monday after receiving multiple 911 calls about a medical emergency involving two children, KABC-TV reported.

When officers arrived, they found the 5 or 6-month-old baby and the 7 or 9-year-old child, according to the Los Angeles, California-based TV station.

Medics pronounced the infant dead at the scene, while the child suffered non-life-threatening injuries, KABC-TV said.

USA TODAY contacted the California Highway Patrol but did not receive an immediate response.

Black sedan seen driving away from child, infant, witnesses say

Witnesses saw a black sedan in the area but the car had driven away before authorities arrived, according to KABC-TV.

No adults were at the scene when the children were found, the TV station said.

"At the moment, it's unknown how those minors arrived onto the freeway. This is where we're requesting the public's assistance," a California Highway Patrol officer said during a news conference.

It is unclear whether the children were hit by vehicles on the freeway, or if they were injured another way.