A police officer at the scene of the Dallas shootings after chaos unfolds at a protest.
A Dallas policeman keeps watch on a street in downtown Dallas, Thursday, July 7, 2016, following reports that shots were fired during a protest over two recent fatal police shootings of black men. (AP Photo/LM Otero)
DALLAS SHOOTINGS: Pictures show chaos unfold after five police officers killed in protests
Gunman and police officer stand off following fatal shootings in Dallas.
Anger boiled over in the crowded streets of Manhattan, where a group of women protesting the deaths were seen being arrested in Times Square. (AFP Photo/Getty Images)
Peaceful demonstrations occurred in New York, Atlanta, Philadelphia, Chicago and Washington DC (pictured above), as well as in Louisiana and Minnesota - where the two black men were killed. (AFP Photo/Getty Images)
Large crows gathered in New York City's Time Square to join peaceful protests. (AFP Photo/Getty Images)
Before the gunfire broke out hundreds of people had marched through Dallas peacefully earlier on Thursday, demanding justice for Alton Sterling and Philando Castile. (AFP Photo/Getty Images)
The popular I-880 in Oakland, CA has graffiti sprayed over it with messages of protest. (Bay Solidarity/Twitter)
The protests continued across the country as protesters blocked the I-880 in Oakland. "Still here, ain't leavin," they chanted on the streets. (Danielle Hirokane/Twitter)
Dallas Police officers shield bystanders after shots were fired in the middle of what had been a peaceful rally in the Texas city. (AP Photo/LM Otero)
Pictured is Mark Hughes, who was pictured walking through Dallas with what appeared to be an assault rifle. He turned himself into police after Dallas Police made a public appeal and his brother insists he was not involved in the shooting. (Dallas Police/Twitter)
President Obama appealed for calm as protests swept the nation on Thursday in the wake of the two shootings. (AP Photo)
Two snipers shot 11 police officers, killing four during a protest in Dallas over the issue of police shootings, police said. (AP Photo)
Dallas Police Chief David Brown said two snipers shot 10 police officers from elevated positions during a protest rally in Dallas, killing three (AFP Photo/Laura Buckman)