 -- Two Georgia police officers have been fired today after videos surfaced online showing a man being punched and kicked during a traffic stop, police said.

The Gwinnett County Police Department in Lawrenceville, Georgia -- about 30 miles outside of Atlanta -- called the videos "shocking" and "disturbing" and announced today that two officers had been fired and that criminal investigations had begun.

The first video to surface shows an officer kicking a handcuffed man in the head as he lays in the middle of a major roadway during a traffic stop. That officer, identified as Master Police Officer Robert McDonald, was terminated today, police said.

A second video discovered by police, taken by a witness from a different angle, "shows the man getting out of the car with both hands up," according to police. "As he stands with his hands up, [Sergeant] Michael Bongiovanni strikes the man in the face," the police said in a statement.

Bongiovanni, a supervisor, was also terminated, the Gwinnett County Police Department announced.

"The revelations uncovered in this entire investigation are shocking. We are fortunate that this second video was found and we were able to move swiftly to terminate a supervisor who lied and stepped outside of his training and state law," the police said in a statement announcing the second officer's termination.

Bongiovanni was hired in 1999 while McDonald joined the department in 2013.

Earlier in the day, Gwinnett County Police Chief Butch Ayers said of McDonald: "This officer and his actions do not represent the men and women of this police department who put their lives on the line."

Ayers said McDonald apologized for what occurred and for embarrassing the department.

"It shouldn't have happened," Ayers said McDonald told him.

The Gwinnett Police Department said in a press release that it has launched a criminal investigation that will be handed over to the District Attorney's Office.

"What happened yesterday was clearly outside of state law and department policy," the police department said. "We do not tolerate actions that are not consistent with our core values or state law."

Police said the incident happened April 12 around 4 p.m. local time. McDonald was responding as a backup officer to assist Bongiovanni with a traffic stop at the busy intersection of Sugarloaf Parkway at Lawrenceville Suwanee Road.

McDonald was “involved in a use of force where a handcuffed man was kicked in the head,” according to the Gwinnett County Police Department. An ambulance responded to the scene and treated the man, police said.

The officer who made the stop reported McDonald to superiors, Ayers said.

The shift commander initiated an “immediate investigation into the incident” after the arrest, the police department said. McDonald was subsequently placed on administrative leave and his department-issued firearm was taken.

“The cellphone video is very disturbing and it speaks for itself,” the Gwinnett County Police Department said of the first video. “The video was very crucial to the investigation and it confirmed that the force used was unnecessary and excessive."

The department added, "Robert McDonald stepped outside of the guiding principles of our agency, and as a result of his actions he was terminated less than 24 hours after the incident occurred. The actions by this former officer do not represent the officers of this department who dedicate their lives to serving the community on a daily basis."

The nearly two-minute video, taken by a witness on a cellphone, appears to show a police officer pull a driver, who is black, from his vehicle and struggle with the man before placing him on the ground and putting him in handcuffs.

Another officer is seen running over to assist and appears to stomp the handcuffed man in the face as he lays on the street. The officers then pick up the man and put him in the backseat of a police vehicle.

Ayers said he felt "mad" and "upset" when he saw the video, adding that the man was "clearly not resisting" and the video "speaks for itself."

"Trust is fragile," Ayers said, referring to relations between police and the communities they serve. "Situations like this one only makes things worse."

Sir Maejor Page, president of Black Lives Matter Greater Atlanta, said his organization has already put pressure on the Gwinnett County Police Department and will continue to do so.

“When I first saw the video, I immediately got the chills,” Page told ABC News. “This is why we take to the street and we scream ‘Black Lives Matter’ because police officers violate us day in, day out.”

A criminal arrest warrant issued Wednesday night and obtained by ABC News identifies the man as 21-year-old Demetrius Hollins of Lawrenceville. The warrant states that Hollins "did knowingly and willfully obstruct or hinder" Sgt. Michael Bongiovanni of the Gwinnett County Police Department by "ignoring verbal commands to exit vehicle and then refusing to place hands behind back after he was told he was under arrest." The warrant further states that Hollins "did physically resist arrest."

According to the police incident report obtained by ABC News, Hollins was driving in a red Acura Integra that did not have a license plate and whose passenger side brake light was out. Hollins also changed lanes three times without a signal. The officer who pulled him over, identified in the incident report as Bongiovanni, said Hollins "began to act strange" and started yelling, "I need to call my mom" and "You have to let me go." The officer also said he smelled marijuana.

Bongiovanni said he then realized he had arrested Hollins in August 2016 for having marijuana and a loaded gun in the car. The officer said Hollins exhibited "strange behavior" during that time and he also screamed about his mother and physically resisted arrest. That's when Bongiovanni requested a backup unit, according to the incident report.

Bongiovanni said he verbally ordered Hollins to exit the car several times and threatened to use his Taser but the man refused.

"Hollins turned away from me and I feared he would reach for a weapon or try to start the vehicle and drive off. In my previous encounter, he reached for a loaded firearm that was under his seat," Bongiovanni stated in the incident report.

The officer said he then pulled Hollins out of the vehicle. Hollins put his hands up at first, but then refused to place them behind his back when the officer got out his handcuffs, the report says. Hollins "spun around and began to actively resist arrest by bending at the waist and trying to push me away," Bongiovanni stated in the incident report.

Bongiovanni said he deployed his Taser on Hollins multiple times and placed him on the ground. The officer said Hollins eventually complied and he was able to handcuff the man. That's when McDonald arrived to assist, according to the report.

Hollins had a bloody lip and nose, and he was examined by a medical unit before he was placed in the officer's patrol vehicle, according to the report.

Bongiovanni and McDonald did not immediately respond to ABC News' requests for comment.

ABC News’ Fergal Gallagher, Janice McDonald, Steve Osunsami, Dennis Powell, Dominick Proto, Jason Volack