A man has been critically injured in Ferguson, Missouri, in an exchange of gunfire with police at a rally marking the anniversary of the killing of unarmed black teenager Michael Brown.
Police said he was armed with a stolen gun and they had been tracking him. They blamed the violence on a small group of people.
Four officers have been placed on administrative leave.
Photos from the scene showed a young black man lying bloodied on the ground.
The wounded man’s has been identified as 18-year-old Tyrone Harris.
The shooting of 18-year-old Michael Brown in Ferguson by white police officer Darren Wilson in August 2014 sparked demonstrations across the United States.