Dallas police say four officers have died after at least two snipers opened fire during protests downtown. Seven other officers were wounded.
Police Chief David O. Brown said police have a suspect cornered in a garage and are negotiating with that person. He says the snipers fired upon officers "ambush style."
Brown had said three officers were killed, and police issued a tweet later saying a fourth officer had died.
Brown says snipers shot from "elevated positions" during a protest over two recent fatal police shootings.
Two snipers apparently shot 10 police officers during protests in Dallas on Thursday night, the city's police chief said in a statement.
A statement from Dallas Police Chief David Brown released by a city spokeswoman said "it appears that two snipers shot ten police officers from elevated positions during the protest/rally."
The gunfire broke out around 8:45 p.m. Thursday while hundreds of people were gathered to protest fatal police shootings this week in Baton Rouge, Louisiana, and suburban St. Paul, Minnesota.
The statement said three officers are deceased, two are in surgery and three are in critical condition.
"An intensive search" for suspects is currently underway, it said. No one is in custody.
Live TV video showed protesters marching along a street in downtown, about half a mile from City Hall, when the shots erupted and the crowd scattered, seeking cover.
Scores of police and security officers were on hand. Police and others hunched behind cars outside a parking garage. Officers with guns drawn were running near and into the parking garage as police searched for the shooter.
TV cameras showed the search for the gunman stretched throughout downtown, an area of hotels, restaurants, businesses and some residential apartments. The scene was chaotic, with helicopters hovering overhead and officers with automatic rifles on the street corners.
Associated Press writer Ezra Kaplan in New York contributed to this report.
Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.