The suspect in the Fourth of July parade mass shooting that left at least seven people dead in Highland Park, Illinois, has been charged with seven counts of first-degree murder, Lake County State's Attorney Eric Rinehart said at a news briefing on Tuesday.

If convicted, the 21-year-old suspect, Robert E. Crimo III, would face a maximum sentence of life in prison without the possibility of parole, Rinehart said.

He said the first-degree murder charges would be followed by dozens of additional charges before the investigation is over. The prosecutor said he would ask that Crimo remain in custody without bail at the suspect's first court appearance, scheduled for Wednesday.

U.S. Vice President Kamala Harris visited Highland Park on Tuesday night, urging the country to "stand together and speak out" on gun safety. 

(With input from Reuters)