An investigation is underway after video surfaced online earlier this week of a confrontation between a police officer and a man in Manhattan.

The video shows an officer and a man boxing on a street in Harlem.

Police say the incident began when the man in the red shirt was stopped for having a pocket knife out in public.

Officials say when the man was approached, he got defensive, and that's when the fight began, leading to his arrest.

Police Commissioner William Bratton said he doesn't think the officer did anything wrong.

"You have no right, no right under New York law to resist arrest, which was what was going on based on what I was seeing in that video," Bratton said. "So in terms of the internal affairs group will now be reviewing the video, as we always do. But my preliminary review of that, I saw nothing inappropriate with the obvious officer's behavior."

PBA President Pat Lynch has also spoken out about the video, saying in part, "The use of force in making an arrest is always ugly but is absolutely necessary and appropriate when the suspect resists."