Five police officers have died and wounded seven others were injured by snipers on Thursday during protests in Dallas that called for justice after the police shootings in Louisiana and Minnesota this week.

One suspect exchanged gunfire with police and was arrested early on Friday morning. A suspicious package was found near the suspect and a bomb squad had begun investigating the threat.

Two others were taken into custody early Friday morning, and during a standoff with police, a fourth told officers bombs were planted all across the city.

After a lengthy standoff with police, the suspect was killed by a police bomb robot. Earlier reports suggested he had shot himself.

Earlier, he said "more will die" and claimed to have planted explosives throughout the area.

No explosives were found in two searches of the downtown area, Major Max Geron said.

Another suspect labeled as a “person of interest” willingly turned himself into police. He was on the ground when shots first rang out, according to several reporters at the scene, and was later released by police.

“We still don’t have a complete comfort level that we have all the suspects,” Dallas Police Chief David Brown told reporters earlier. “We will continue a rigorous search of downtown until we are satisfied that all suspects have been captured.”

Chief Brown said that two suspects were perched atop downtown parking garages and had purposely targeted officers. "They planned to injure and kill as many law enforcement officers as they could,” he said.

Police officers killed by sniper at protests in Dallas Show all 20 1 /20 Police officers killed by sniper at protests in Dallas Police officers killed by sniper at protests in Dallas A Dallas Area Rapid Transit police officer receives comfort at the Baylor University Hospital emergency room entrance in Dallas Dallas Morning News/AP Police officers killed by sniper at protests in Dallas Emergency services help an unknown patient on a stretcher as law enforcement officials stand nearby at the emergency receiving area of Baylor University Medical Center AP Police officers killed by sniper at protests in Dallas Dallas Police shield bystanders after shots were fired, during a protest over two recent fatal police shootings of black men AP Police officers killed by sniper at protests in Dallas Bystanders run for cover after shots fired at a Black Live Matter rally in downtown Dallas AP Police officers killed by sniper at protests in Dallas Police check a car after snipers opened fire on police officers in Dallas AP Police officers killed by sniper at protests in Dallas A man raises his hands as he walks near a law enforcement officer, following the shootings of several police officers in downtown Dallas AP Police officers killed by sniper at protests in Dallas A Dallas police officer steps out of a vehicle as he arrives in front of Baylor University Medical Center AP Police officers killed by sniper at protests in Dallas Dallas police officers face protesters on the corner of Ross Ave. and Griffin street after police officers were shot during a peaceful protest in Dallas EPA Police officers killed by sniper at protests in Dallas A Dallas police officer covers his face as he stands with others outside the emergency room at Baylor University Medical Center AP Police officers killed by sniper at protests in Dallas Law enforcement officials escort a couple in through the emergency room entrance at Baylor University Medical Center AP Police officers killed by sniper at protests in Dallas Dallas Police respond after shots were fired at a Black Lives Matter rally in downtown Dallas AP Police officers killed by sniper at protests in Dallas Dallas Police respond after shots were fired at a Black Lives Matter rally in downtown Dallas AP Police officers killed by sniper at protests in Dallas Police cars sit on Main Street in Dallas following the sniper shooting during a protest AFP/Getty Images Police officers killed by sniper at protests in Dallas A Police officer stands guard at a barricade following the sniper shooting in Dallas AFP/Getty Images Police officers killed by sniper at protests in Dallas Police stand near a barricade following the sniper shooting in Dallas AFP/Getty Images Police officers killed by sniper at protests in Dallas Dallas police check a car after detaining a driver after a shooting in downtown Dallas AP Police officers killed by sniper at protests in Dallas Dallas police order people away from the area after several police were shot in downtown Dallas AP Police officers killed by sniper at protests in Dallas Dallas police move to detains a driver after several police officers were shot in downtown Dallas AP Police officers killed by sniper at protests in Dallas Dallas police detain a driver after several police officers were shot in downtown Dallas AP Police officers killed by sniper at protests in Dallas Dallas Police respond after shots were fired at a Black Lives Matter rally in downtown Dallas Dallas Morning News/AP

“We are reaching out to the families of these officers and bring them to the hospitals,” Chief Brown said during a press conference. He also encouraged anyone with information on the attacks to come forward.

Brent Thompson and Patrick Zamarripa were the first victims to be named.

At least two civilians were injured during the attack.

One of them, Shetamia Taylor, was at the protest with her four sons, who are 12 through 17-years-old.

Her sister said Ms Taylor threw herself over her sons when the shooting began. She was undergoing surgery after being shot in the right calf.

The Dallas Public Transportation System (Dart), announced on Twitter that all bus and rail services had been suspended after the attacks. The Federal Aviation Administration also issued a temporary restriction on all flights over the downtown area.

Facebook has also activated its Safety Check feature to help people living in the area.

Several videos with audible gunshots surfaced on social media showing police, bystanders and reporters scrambling to take cover from the gunfire.

The demonstrations began following the police killings of two black men in Louisiana and Minnesota this week. Both incidents were captured on video and quickly made headlines due their graphic nature, fueling movements calling for racial equality and unbiased policing across the states.

President Barack Obama addressed the nation on Thursday night calling for the elimination of racial bias in policing across the country.

“To be concerned about these issues is not political correctness. It’s just being an American,” President Obama said while visiting in Poland. “And to recognize the reality that we got some tough history and we haven’t gotten through that history yet.”

The first victim, 37-year-old Alton Sterling, was pinned down to the ground by two Baton Rouge Police officers on Tuesday morning when he was shot multiple times in the chest and back. He was pronounced dead a the scene.

The second victim, 32-year-old Philando Castile, was fatally shot by an officer on Wednesday in Falcon Heights in front of his girlfriend and her 4-year-old daughter. Diamond Reynolds live streamed the incident on Facebook while the officer still held his gun on her deceased fiancé.

Thursday night's protests were organized by the Next Generation Action Network, not Black Lives Matter as there is no local chapter in the city, Dallas Morning News reports. Still, leaders of the Black Lives Matter movement condemned the violence.

"#BlackLivesMatter advocates dignity, justice and freedom," they wrote on Twitter. "Not murder."

Richard Adams, a witness to shooting in Dallas, said the protests were “peaceful and lovely” until he heard what sounded like “a bunch of firecrackers going off.”