DEVELOPING: At least two police officers were shot Thursday night in downtown Dallas during a protest over the recent fatal shootings of African Americans by police. Fox News' Dallas affiliate KDFW-Fox4, citing a uniformed officer, reported that the officers were shot, but their conditions were unknown.

Fox4 is reporting that there are believed to be at least two gunmen, one of whom was reported down, while the other — wearing what was believed to be a bullet-proof vest and tactical gear — was in a nearby garage, where police reportedly were egotiating for his surrender.

Fox4 also was reporting that as many as six officers were wounded in the shooting, but that was not confirmed.

Fox4 cameras captured protesters ruing away from the scene of the shooting shortly before 9 p.m. local time. A cameraman approached the scene and captured officers apparently lying on the ground.

A Fox4 reporter said he heard approximately 10 gunshots downtown. That reporter was told by an officer police were searching for someone with a rifle.

The status of the shooter was not immediately clear. Aerial images showed officers appearing to focus their search on a parking garage.

Witness Carlos Harris told the Dallas Moing News the gunfire was "strategic. It was tap-tap-pause. Tap-tap-pause."

Michael Batista told KDFW the protest march had been "very peaceful" before the shooting started.

Brittany Peete, a demonstrator, told the Associated Press she didn't hear the gunshots, but she "saw people rushing back toward me saying there was an active shooter."

Peete said she saw a woman trip and nearly get trampled as people ran to get to safety.

"Everyone just started ruing," Devante Odom, 21, told The Dallas Moing News. "We lost touch with two of our friends just trying to get out of there."

The Associated Press contributed to this report.