Video: Police officers shot dead during Black Lives Matter street protest

(AAP)
(AAP)

A person suspected of involvement in the Dallas shooting holed up in a garage was killed by a bomb robot, Dallas' police chief has confirmed.

David Brown says negotiations broke down after several hours and the suspect was firing upon officers when the decision was made to send in the robot. An explosive was attached to the robot and the suspect was killed when it detonated.

It was the best option to protect the safety of the officers, Mr Brown says.

An anti-violence protest turned deadly when two snipers shot at police "ambush-style" from elevated positions. Five have died while seven others are injured, with some requiring immediate surgery while others were in a critical or serious condition.

Three of the officers died at the scene, while the other two died in the hours following the attack.

It's reported to be the deadliest day for US law enforcement since the 9/11 attacks in 2001.

Two civilians were also been wounded.

Local media reports the suspect at the centre of the parking garage siege died of a self-inflicted gunshot wound.

A woman has been taken into custody after a shoot-out with SWAT officers in a two-storey garage. Police spent several hours exchanging gunfire with another suspect in the garage, who told them "the end is coming" and claimed bombs are "all over the place", including around the garage and downtown.

Two other people who were seen leaving the scene of the shooting in a black Mercedes at high speed have also been taken into custody. An officer had seen one of them carrying a camouflaged bag and walking quickly down Lamar St, before throwing the bag into the car and driving off.

The hunt for more suspects is continuing, an intense search throughout the night expected to continue throughout the day, until police are sure all suspects have been interrogated.

Mr Brown says they will leave no stone unturned.

"If there's somewhere out there that's associated with this, we will find you, and we will prosecute you, and we will bring you to justice."

It's understood none of the suspects are co-operating with police.

Police had earlier identified a person of interest, but he was cleared of any involvement after handing himself in and has been released.

It's believed all the suspects were working together and the bomb squad has secured one suspicious package after reports a bomb was planted at the scene. No other bombs have been found in further sweeps.

The suspect who was killed had told police he wasn't affiliated with any groups and that he was alone.

Protestors were marching on the downtown street as part of a peaceful Black Lives Matter rally, chanting "hands up, don't shoot", when gunfire broke out.

Panic spread quickly as more than a thousand people ran for their lives, and witnesses describe it as a "warzone".

Mr Brown has praised the "great courage" shown by officers at the scene, who reportedly ran towards the gunfire and transported the injured to hospital in their patrol cars rather than wait for ambulances.

"You see video footage after video footage running toward gunfire from an elevated position with no chance to protect themselves, and to put themselves in harm's way to make sure citizens can get to a place of security.

"[Law enforcement officials] don't feel much support most days. Let's not make today most days," Mr Brown says.

Several people filmed the chaos on their cellphones and put it on social media.

Livestreaming website Periscope.tv has allowed those who live in the city to keep the public updated during the stand-off. User Gregarro lives opposite the parking garage where police were negotiating with a suspect and more than 20,000 people have tuned in to his coverage.

He admits some people have contacted him, worried the stream allowed the suspect holed up in the garage to stay updated with the police action.

But he was unconcerned, saying if the suspect was watching, "God help you". 

Dallas Mayor Mike Rawlings has asked the public to stay away from the scene as the investigation continues.

"To say these police officers put their lives on their line every day is not a hyperbole - it's a reality," he says.

After the shooting the hashtags "#BlueLivesMatter" and "#BackTheBlue" began picking up traction online, while the Omni Hotel in the city reportedly lit up in tribute.

Texas is an open-carry state, meaning citizens have the right to carry firearms in public. It makes the hunt for those responsible for the shooting all the more difficult as witnesses are unable to tell who is simply carrying a firearm because they have the right to, versus who may have taken part in the shooting.

There have been street protests across the US after two black men were shot dead by police in separate incidents in the past 48 hours. Both shootings were captured on cellphone cameras and shared widely on social media, sparking outrage.

Law enforcement officials had attempted negotiations with the armed suspect holed up in a parking garage over the course of several hours before sending in the bomb robot.

During the talks, the suspect told them he "wanted to kill white people, especially white officers".

The shooting, which he says he was alone responsible for, was motivated by recent incidents where police shot and killed black people, seemingly without provocation.

Police would "eventually find" the improvised explosive devices (IEDs) around the city, the suspect said.

"The suspect said other things that are part of this investigation, so we can make sure everyone associated with this tragic event is brought to justice," Mr Brown says.

"So we won't expand any further on what other suspects we have looked at, or interviewed, or their status, until we get further into this investigation and get closer to a conclusion on who are all involved."

Earlier reports from local media suggested the suspect had died from a self-inflicted gunshot wound but Mr Brown confirms he died when they sent in the explosive.

Video: Police officers shot dead during Black Lives Matter street protest

(Reuters)

US President Barack Obama has been briefed on the shootings from where he is currently in Warsaw, Poland.

In a televised statement he promised the federal government will provide support to the state in the wake of the "tremendous tragedy".

He calls it a "vicious, calculated and despicable attack on law enforcement", promising that "justice will be done".

"Let's be clear - there is no possible justification for these kind of attacks."

Mr Obama also alludes to his push for nationwide gun control.

"We also know that when people are armed with powerful weapons, unfortunately it makes attacks like these more deadly and more tragic. And in the days ahead we are going to have to consider those realities as well." 

Only yesterday Mr Obama addressed the nation after video was released of a Minnesota man shot by a police officer.

"Today, our focus is on the victims and their families," he says.

Newshub.