MILWAUKEE (CBS 58) — A Silver Alert has been issued for a 71-year-old Milwaukee man who was last seen Wednesday afternoon.

The Milwaukee Police Department is searching for Johnny Ray Brock, who was last seen around 3 p.m. in the 2400 block of North 39th Street.

Police say Brock is critically missing.

Brock is described as a Black man who is about 6 feet, 3 inches tall and weighs approximately 220 pounds. He has brown eyes and a gray beard.

He was last seen wearing a black-and-gray sweatshirt, gold pants and white Nike shoes.

Authorities believe Brock is traveling on foot.

Anyone with information about Brock's whereabouts is asked to contact the Milwaukee Police Department.