Editor's note: This continuing story was last updated at 3:14 a.m.

DALLAS — Dallas Police Chief David Brown has confirmed at least 11 police officers were shot and at least five were killed in an attack by two snipers in downtown Dallas at a protest of officer-involved shootings across the country on Thursday night.

Dallas police sources confirmed to News 8 early Friday one suspect is dead after a long standoff with police. A female suspect was taken into custody earlier in the night. It is unclear at this time if they are the only suspects involved.

The Dallas Police Association announced the fifth officer had died at about 1:45 a.m. One DART officer and four Dallas Police officers have died.

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DART had said a total of six officers were killed briefly early Friday morning before issuing a correction -- only five are confirmed dead. Still, it is the deadliest since event for police officers in the United States since September 11, 2001.

One bystander who is not a police officer, Shetamia Taylor, was also shot. She is expected to recover.

The Dallas Police Department said in a statement around 11:30 p.m. a female suspect who was in a shootout with Dallas SWAT officers near the garage at El Centro College in downtown is in custody. A suspicious package was discovered near that suspect's location and the DPD bomb squad headed to the scene.

In a 12:30 a.m. news conference Brown said the police are negotiating with a second suspect on the second floor of that same parking garage. He said the suspect had exchanged gunfire with police during the negotiations, which have lasted more than 45 minutes as of 12:30 a.m.

Brown said the suspect told negotiators "the end was coming," that he's "going to hurt and kill more of us" (meaning law enforcement), and that there were bombs planted all over the garage and downtown.

The police chief said he would be meeting with officers shortly after the news conference to discuss their plan to end the negotiations and capture the second suspect.

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Chief Brown also said the department would continue to search downtown throughout the night and into the morning until they are sure all suspects have been captured and they have determined there are no bombs.

Meanwhile, a massive police presence surrounded a vehicle and are questioning two individuals they took into custody on Interstate 35 at Ann Arbor Avenue in Dallas.

According to Dallas police, that situation began when a Dallas police officer saw an individual carrying a camouflage bag walking quickly down Lamar Street. The individual threw the bag into black Mercedes, when then sped off at a high rate of speed.

Officers followed the vehicle southbound on I-35 and stopped it on I-35 at Kiest. Police are questioning both occupants of the vehicle.

None of the suspects or persons of interest have been identified.

Earlier Thursday, Dallas police circulated a photo of a person of interest in the crime earlier in the night. They say that man has since turned himself in, in addition to the suspect who was in a shootout with DPD officers.

Brown initially said 10 officers were shot, but a short time later said an 11th officer had been shot in an exchange of gunfire with one of the suspects.

It remains an active-shooter situation. Police have asked everyone to get to safety and avoid downtown Dallas. If you have any information regarding the shooting, DPD asks you to call 214-671-3485.

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The shot officers include both Dallas police and DART officers. They have been taken to both Parkland Hospital and Baylor Medical Center.

Brown said three of the dead officers were with the Dallas Police Department and one was with the DART police.

The shots were fired as the march was moving down Lamar Street near Griffin before 9 p.m.

An officer at the scene told News 8's Marie Saavedra the shooter had a rifle. She described several volleys of quick bursts of gunfire.

Another bystander, Richard Adams, said the protest was "a lovely, peaceful march," until they were walking down Commerce Street near the Bank of America building parking garage when he heard what sounded like "a bunch of firecrackers going off."

"Everybody just stopped -- 'Run, run for your lives!' Women with children and babies and everybody was chaotically running. And then, maybe I was a half-a-block away, calming down a little bit when we heard it again. [...] There must have been five times tonight -- whenever we thought we were safe, people said 'Run, people were shot!'"

Dallas Mayor Mike Rawlings said that the White House and the Governor's Office had called Thursday night to offer condolences and any assistance they could.

"Our thoughts and prayers are with the Dallas law enforcement community and the Dallas Area Rapid Transit (DART) officers killed and injured this evening," said Texas Gov. Greg Abbott in a statement. "I've spoken to Texas Department of Public Safety Director Steve McCraw and have directed him to offer whatever assistance the City of Dallas needs at this time. In times like this we must remember - and emphasize - the importance of uniting as Americans."

El Centro College has announced classes are cancelled on Friday. If you work downtown, officials say you should check DallasCityNews.net in the morning to determine if there will be any delays or cancellations.

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