These photos show the immediate aftermath of the shootings in Dallas
Five of the police officers are dead, and seven others are wounded.
One of the main suspects involved in a shootout with police, identified as 25-year-old Micah Johnson, was killed by a police robot bomb. At least three more suspects were taken into custody Friday morning.
Many Dallas streets are now closed, and some flights into the city have been cancelled.
The rally was one of many to take place across the country last night after two black men were killed by police in Minnesota and Louisiana this week.
Here are some photos taken in the shootings' immediate aftermath: