President Barack Obama greets people in the audience after participating in a town hall with ABC news anchor David Muir, officers, parents, students, community leaders and families on trust and safety in communities, Thursday, July 14, 2016, in Washington. (AP Photo/Carolyn Kaster)

The first person to address President Obama on Thursday was 15-year-old son of Alton Sterling, who was killed only a week ago by police outside a convenience store in Baton Rouge, La. A video of his father's death would spur anger and protests across the country.

"I ask that you keep all of these families and my families safe," said Cameron Sterling in a hushed voice. "I ask for your help to unite all of the races of the world."

Then came Diamond Reynolds, who live-streamed the death of Philando Castile, her fiance, on the internet after he pulled over and shot by police in Minnesota. Her four-year-old daughter was sitting in the back of the car.

"When I think about my daughter's future I am scared for her," Reynolds told Obama.  "How do we as a nation stop what has happened to my family and all the other victims across the world?"

Sterling and Reynold's addressed the president as part of a town hall meeting on race and policing that was led by ABC News anchor David Muir. The meeting was remarkable less for the president's remarks than for the questions he fielded, which came from staunch critics, the mothers of police officers as well as Sterling and Reynolds, who were still reeling for grief.

The deaths of Sterling and Castile led to widespread protests decrying the treatment of black men by police. At one of those demonstrations in Dallas on Friday a black gunman opened fire, killing four white and one Latino police officers.

"I think that the place to start is for everybody to recognize that we need police officers and we need those police officers to be embraced by the community," Obama told Reynolds. "If there are good relations between police and those communities, then the communities are going to be safer and police officers will be safer. ...we should have a common goal."

In the last week Obama has addressed the public at least a half-dozen times in speeches, news conferences and at a memorial service on Wednesday in Dallas. He has called for calm, understanding and unity, insisting repeatedly that the country is not as divided as it seems.

On Thursday Obama fielded a question from Lt. Gov. Dan Patrick, a Texas Republican, who blamed the Black Lives Matter movement for the Dallas deaths, called the protesters "hypocrites," and chastised Obama for "divisive" rhetoric.

Standing before the president, Patrick's tone was more measured, asking Obama whether police officers "really, in their heart, feel like you're doing everything you can to protect their lives?" He then called on Obama to illuminate the White House in blue lights in tribute to the fallen police.

"The police have asked you to do that," he told the president. "You've done it for other groups. It would send a strong message."

Obama said that he had been "unequivocal in condemning any rhetoric directed at police officers" and and rejected the critique that he not praised police for doing tough and dangerous work.

"I appreciate the sentiment." Obama said in a clipped tone. "I think it's already been expressed, but I'll be happy to send it to you in case you missed it." The president also referred to data that show blacks and Latinos are more likely to be stopped, searched and arrested than whites.

"This is not just stuff I make up," Obama said. "I'm aware that my words matter deeply here."

A mother of a Baltimore police officer whose son was pelted with bricks and water bottles last summer in the riots there asked Obama about her son's treatment.

"What's he supposed to do, you know? What's he supposed to do to protect himself?" asked Teri George, referring to her son. "It just seemed like nobody was there to protect him."

Obama told her to be proud of her son and insisted that Americans needed to do more for impoverished and forgotten inner-city communities.  "One of the challenges we end up having though is, is that if in some of these communities in Baltimore all these tensions have built up for so long," he said. "That's why we have to do everything we can to create healthy communities. That will make life easier for your son."

The last person to address Obama was a woman who had been protesting in Dallas with her son when the killer opened fire, hitting her in the leg. She told Obama, through tears, that one of the officers had jumped on her and her son to shield them from the bullets. "I saw another officer get shot right in front of me," she said.

Obama met with the woman and her teenage son when he was in Dallas on Wednesday for the memorial service. He also met with the families of the fallen officers.

"That's always the hardest thing I do as president, trying to comfort a family who has just lost somebody," Obama said. "You had some white children who had lost their father. You had Latino children who had lost their father. You have African- American families who have lost their fathers. And I can tell you the grief is the same. The loss is the same...These are all our kids and we want an America where they feel safe and loved and cared for."