DALLAS _ At least four police officers were killed, and at least seven others shot Thursday night by two snipers in downtown Dallas near the end of a protest of officer-involved shootings in other cities, Dallas police Chief David Brown said.
Dallas Mayor Mike Rawlings described the shooting "as our worst nightmare."
Dallas police have arrested one suspect who had been cornered in the parking garage of El Centro College.
Brown said that the suspects may have planted a bomb downtown and that police found a suspicious package near where one suspect was arrested.
Dallas police released the photo of one suspect who later turned himself in, but Twitter reaction said the man in the photo was not involved in the shooting.
Three of those killed were Dallas police officers and the third was an officer with DART, or Dallas Area Rapid Transit.
"Three officers are deceased, two are in surgery and three are in critical condition," Brown said.
A WFAA photographer near the scene recorded the sound of gunfire, which he said was from a semi-automatic weapon. A reporter said she heard three dozen shots, while some witnesses said they heard 50-70 shots and saw the shooter pause to let the protesters go by before targeting officers.
Police called for the public to leave downtown.
The protest was scheduled in downtown Dallas after Alton Sterling was killed by an officer in Baton Rouge, La., and Philando Castile was killed in Falcon Heights, Minn. The shootings were captured by cellphones.
Soon after the shooting, the Fort Worth Police Association tweeted "Pray for our friends" in the Dallas Police Department.
