Authorities in Dayton, Kentucky, are set to investigate after a video of a police officer leaving his unattended rifle on a car went viral.

The video, posted by Matt Haas (matt.haas.73157) on Facebook, on Thursday, 25 January, has gained more than 190,000 views.

In the clip, multiple officers can be seen engaging with a suspect on the opposite side of the street while a rifle is shown leaning against a parked car.

At one point, a teen walks by the weapon but does not notice it. Later in the video, one officer can be seen walking down the street with a man while two others walk in the opposite direction — leaving the weapon completely unattended. A person is subsequently heard in the video, yelling, "All walking away. There's an assault rifle left unattended." It is only then that an officer comes over and takes the gun to put it back in the patrol car.

According to Fox News, both Dayton and Bellevue police officials were responding to a domestic violence incident in which there were possible shots fired.

The Bellevue Police Department said the suspect, who was later taken into custody, had initially told officers that he would only cooperate if they did not bring their rifles along.

"To establish a rapport, and end this situation peacefully, the Bellevue officer handed his patrol rifle to a Dayton police officer for safekeeping," the statement read.

According to an internal review by the Bellevue Police Department, it was revealed that the officer did not leave the rifle unattended, the Fox News website reported. They also released a body camera footage "in an effort to show transparency".

"The footage clearly shows that no Bellevue officer left a patrol rifle unattended," the statement read.

Meanwhile, Dayton Police Chief David Halfhill said in a statement, "It is unfortunate that this accident happened, but we as police officers are human and do make mistakes."

"We hold our police officers to a higher standard and be assured that this mistake will be fully investigated."

According to Fox News, Halfhill acknowledged the mistake that "another agency's patrol rifle was accidentally set down when the officers were going 'hands on' with the suspect". But he also added that the officers responding to the incident did a "great job" due to the fact "that no one was injured".