Officers responded to a report of a shooting near 14th and H streets at about 12:10 p.m., according to Union City police.
Responding officers found a male victim suffering from gunshot wounds. Police did not release details about the condition of the victim, who was taken to a local hospital.
James Logan High School and Searles Elementary School were placed on temporary lockdown, which was lifted within two hours. New Haven Unified School District administrators sent out an automated message to parents regarding picking up students.
A possible suspect was seen leaving the area in a white full-sized pickup truck, with racks similar to lumber racks, police said.
The suspect was described as a Hispanic man in his 20s with a stocky build, short brown hair and a light brown beard. Witnesses said the suspect was wearing a bright yellow construction vest.
Anyone with information about the shooting is asked to contact the Union City Police Department at (510) 675-5225 or the anonymous tip line at (510) 675-5207.