Pictured: Newlywed transit officer and military veteran among 5 Dallas sniper victims

Two of the five officers shot dead by snipers in downtown Dallas Thursday night have been identified.

The five officers were killed and seven others were injured when gunmen opened fire at 8.45 p.m. local time Thursday, according to the mayor's office. Two civilians were also wounded.

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

Read: Police Shooting Victim Philando Castile Was 'a Very Good Person ... Just Black in the Wrong Place'

Thompson, 43, was the first Dallas Area Rapid Transit officer to be killed in the line of duty since the department was established in 1989.

DART Chief James Spiller told the Today show Friday that the officer, who joined the agency in 2009, had married another DART officer just last month.

"Our hearts are broken," DART said in a statement.

Before joining DART, Thompson worked with U.S. police officers in Iraq and Afghanistan for the military contractor Dyncorp, according to his LinkedIn page.

See more from the tragedy in Dallas:

Another slain officer, Patrick Zamarripa, was identified by his family on Twitter. His stepbrother, Dylan Martinez, shared a photo of Patrick with his father.

Read: Celebrities React to Police Shooting Deaths of Alton Sterling and Philando Castile

"No father should have to bury his son. You are a hero, Patrick. Love you man," he wrote. Zamarripa was a family man and a military veteran, he said.

On Zamarripa's own Twitter page, he had written: "Addicted to the thrill of this job. I own the night. I love my Country, Texas, Family, God, Friends, and Sports! Don't Tread on Me! 'Merica."

Photos on social media show him with his young children.

Photos show Patrick Zamarripa, one of the officers shot dead in Dallas Thursday. (Photo credit: Twitter)

The other victims are believed to be Dallas police officers, but have not yet been identified. On Friday morning, Police Chief David Brown said most of the injured officers had been released from hospital.

Family told NBC5 that Shetamia Taylor, 37, was among the civilians injured in the gunfire. She was shielding her children from the bullets, her sister told the channel. Her condition is not known.

The shootings unfolded when anti-police brutality marches were underway following the deaths of Alton Sterling in Louisiana and Philando Castile in Minnesota. Both men were shot by police officers in incidents that are now under investigation.

One suspect was killed in an explosion detonated by police following a standoff Thursday night, Chief Brown said Friday, denying reports that the gunman had killed himself. Before his death, the suspect said he wanted to kill white people, especially white officers, Brown said.

The suspect told police that he had acted alone and, on Friday, authorities stayed quiet on how many other suspects they are seeking. "We want to keep these suspects guessing," Brown said.

He shared his heartbreak in the wake of the violence.

"We're hurting," he said. "Our profession is hurting... We are heartbroken. There are no words to describe the atrocity that occured to our city. All I know is that this must stop, this divisiveness, between our police and our citizens...

"Please pray for our strength during this trying time."

Watch: Mother of Philando Castile is 'Outraged' Over Son's Death By Police Officer