Police in Ferguson, Missouri say a man is hospitalized and in critical condition after being shot by police in an exchange of gunfire.

The shooting took place on what had been a day of peaceful demonstrations in Ferguson. The protesters were marking the one-year anniversary of the shooting death of an unarmed black teenager by a white police officer.

St. Louis County police said four officers had been watching a man who they thought might be carrying a gun. Police said the man was involved in an exchange of 40 or 50 gunshots between two groups of people before shooting the officers’ vehicle many times. The four officers exchanged shots with the man.

The Saint Louis Post-Dispatch newspaper says the man’s father identified him as 18-year-old Tyrone Harris, Jr.

Mr. Harris’ father reportedly said his son was a friend of 18-year-old Michael Brown, who was killed by police in Ferguson last year.