Police and other law enforcement are on high alert following the shootings during a Dallas protest that left five officers dead and seven others wounded.
Security expert and former police officer Steve Kardian told Inside Edition: "Based on the current political climate, how could a police officer walk the street and feel safe in this time and era?"
The protest in Dallas was in response to two black men who were shot by police earlier in the week.
The protests, intended to be peaceful, were carried out in Dallas, New York and Oakland, among other places.
Retired NYPD detective Harry Houck broke down in tears Friday as he spoke to CNN about the killings of the Dallas police officers
"You have a 9mm handgun; you are taking on somebody with an automatic weapon. You have a bullet-proof vest that will not stop that round. I hope people can really appreciate what these police officers did," he said.
In 2014, NYPD officers Wenjian Liu and Rafael Ramos were gunned down as they sat in their squad car in Brooklyn. The lone gunman, Ismaaiyl Brinsley, was seeking revenge for the deaths of Eric Garner and Michael Brown, who died at the hands of the police earlier that year.
Brinsley later turned the gun on himself in a nearby subway station when police responded to the scene.
At the time of the killings of officers Liu and Ramos, New York Police Commissioner Bill Bratton said: “No warning, no provocation — they were quite simply assassinated, targeted for their uniform.”
“An officer today has to have their head on a swivel. They need to check all around them,” Kardian said. “They can’t drop their guard for a moment. They gotta be alert. They gotta have situational awareness.”