The officers were checking three people when a fourth suspect opened fire.

While the authorities initially believed all four were suspects in the shooting, the arrested man was actually the only suspect, AP reports, citing O'Dell.

Police identified that suspect as Everett Glenn Miller, a 46-year-old African-American male.

Miller had posted violent anti-police comments on social media but it was not reported to authorities, according to O'Dell.

"We've got to come together as a nation and get our community involved," Police Chief O'Dell said at a news briefing on Saturday, commenting on the nationwide surge in violence against law enforcement.

US President Donald Trump responded to the Kissimmee shooting, tweeting: "My thoughts and prayers are with the KissimmeePolice and their loved ones. We are with you!"

In the northern Florida city of Jacksonville, two police officers were shot and wounded while responding to reports of a gunman in an apartment, the Jacksonville Sheriff's Office said.

According to the sheriff's office, officers were responding to an attempted suicide call where there were "three additional victims inside the house that had retreated to a back bedroom for their safety. While the officers were en route, the suspect armed himself with a high-powered rifle."

The suspect opened fire through the door, injuring two officers, but was killed as they returned fire. "He engaged the officers before they made entry into the house," police said.

One officer was said to be in critical condition, while another was stable. Jacksonville police did not elaborate on details, announcing further updates later in the day.

During the same night on Friday, two Pennsylvania state troopers were also shot in the city of Fairchance. Both officers were said to be in stable condition and were expected to survive, while the suspect was killed.

"Two state troopers [were] shot and [the] suspect is deceased," Pennsylvania State Police spokeswoman Melinda Bondarenka told ABC News. "We are not releasing any more details at this time."

"I can confirm that one state police trooper was brought to Uniontown Hospital for treatment of injuries suffered in a shooting incident in Fairchance this evening. The injuries suffered by this officer are not life threatening," Josh Krysak, a spokesman at Uniontown Hospital, told the broadcaster.

The 19-year-old attacker's name is reportedly Artur Gadzhiev, who comes from a family originally from the southern Russian Republic of Dagestan, various Russian media speculated citing local investigative officials.

Telegram public channel Mash also reported that Gadzhiev's father, Lametulakh, was known to police as an "extremist" and "supporter" of radical Islam.

Mash published what it said was an actual photo of Gadzhiev, whose neat appearance and smile triggered a frenzy among social media users.

Interestingly, the stabber was initially identified by some Russian media as a 23-year-old Tajikistani national by the name of Bobichel Abdurakhmanov, the claim that soon proved false.

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Other claims that have also emerged locally said the suspect could have worked as security guard at a Surgut supermarket.

An activist of a grassroots group checking supermarkets for products' shelf lives claimed he recognized the assailant shot dead by police as a security officer from one of the city's chain stores.

Posting a grab from one of his videos on Russia's VKontakte (In Contact) social network, the activist alleged "this young man was employed as a security guard at a local grocery store."