Michigan State Police officials are investigating after a motorist walking on the shoulder of an interstate exit in Detroit to get more gas for his car was critically injured in a hit-and-run crash Saturday afternoon, the agency said.

The motorist, identified by law enforcement as a male, was driving on westbound Interstate 96 near Greenfield Road when he ran out of gas. Officials said he was walking up the shoulder of the interstate exit toward Greenfield Road around 2:45 p.m. when he was hit by a vehicle whose driver left the scene after the crash.

The agency said the male, whose age hasn't been disclosed, was taken to the hospital in critical condition.

Investigators said the vehicle that hit the male is black. They were working to learn more about the vehicle and driver on Saturday afternoon by looking at surveillance cameras and debris left at the scene. 

Anyone who saw the crash is asked to call the Michigan State Police at 734-287-5000.