The American Civil Liberties Union of Minnesota is calling for an investigation of a southwestern Minnesota police officer after viewing dashcam video showing the officer violently beating a suspect whose car he stopped.

The ACLU released footage from a July 28, 2016 stop of Anthony Promvongsa in Worthington, Minn., showing Buffalo Ridge Drug Task Force Agent Joe Joswiak running up to the car screaming profanities, then kneeing and punching Promvongsa while the driver is still in the car, his seat belt buckled. The footage then shows Joswiak pulling Promvongsa out of the vehicle and forcibly subduing him.

"The entire incident from when the vehicle is pulled over to when Promvongsa is under arrest and in the backseat of the vehicle handcuffed is less than two minutes. Promvongsa was not given proper time to obey the officer's orders before excessive force was used against him," the ACLU said.

"We are calling for an investigation of Agent Joswiak's behavior and for him to be held accountable for his brutal attack on Anthony Promvongsa, up to and including termination and prosecution," ACLU Minnesota executive director Teresa Nelson said in a statement. "Thus far, Agent Joswiak has received no punishment for this abhorrent treatment of Anthony. This sends a message that the department condones the officer's behavior, which it should not."

Because the case is awaiting a jury trial date, the Buffalo Ridge Drug Task Force, Worthington Police Department and the Nobles County Attorney's Office said in a joint statement it would be inappropriate to comment in a detailed way.

"The video, viewed in a vacuum, shows only a short segment of the incident that is the basis of the criminal charges," the law enforcement statement said, noting that the charges against Promvongsa include two counts of assault with a dangerous weapon (a motor vehicle), one count of fleeing an officer in a motor vehicle and possession of a small amount of marijuana, and driving after revocation

The ACLU said the incident began when off-duty police officers accused Promvongsa of driving recklessly and that Promvongsa denies any conduct that would warrant a "brutal attack" after being stopped.

"I had no idea what was going on when I was approached and attacked by this officer," Promvongsa said in a statement. "I did not even have the opportunity to take off my seatbelt."